Geometry Base

abstract module provides base classes for parametric curves, surfaces and volumes contained in this library and therefore, it provides an easy way to extend the library in the most proper way.

Inheritance Diagram

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Abstract Curve

class geomdl.abstract.Curve(**kwargs)

Bases: SplineGeometry

Abstract base class for defining spline curves.

Curve ABC is inherited from abc.ABCMeta class which is included in Python standard library by default. Due to differences between Python 2 and 3 on defining a metaclass, the compatibility module six is employed. Using six to set metaclass allows users to use the abstract classes in a correct way.

The abstract base classes in this module are implemented using a feature called Python Properties. This feature allows users to use some of the functions as if they are class fields. You can also consider properties as a pythonic way to set getters and setters. You will see “getter” and “setter” descriptions on the documentation of these properties.

The Curve ABC allows users to set the FindSpan function to be used in evaluations with find_span_func keyword as an input to the class constructor. NURBS-Python includes a binary and a linear search variation of the FindSpan function in the helpers module. You may also implement and use your own FindSpan function. Please see the helpers module for details.

Code segment below illustrates a possible implementation of Curve abstract base class:

from geomdl import abstract

class MyCurveClass(abstract.Curve):
    def __init__(self, **kwargs):
    super(MyCurveClass, self).__init__(**kwargs)
    # Add your constructor code here

    def evaluate(self, **kwargs):
        # Implement this function
        pass

    def evaluate_single(self, uv):
        # Implement this function
        pass

    def evaluate_list(self, uv_list):
        # Implement this function
        pass

    def derivatives(self, u, v, order, **kwargs):
        # Implement this function
        pass

The properties and functions defined in the abstract base class will be automatically available in the subclasses.

Keyword Arguments:

id: object ID (as integer)
precision: number of decimal places to round to. Default: 18
normalize_kv: if True, knot vector(s) will be normalized to [0,1] domain. Default: True
find_span_func: default knot span finding algorithm. Default: helpers.find_span_linear()

property bbox

Bounding box.

Evaluates the bounding box and returns the minimum and maximum coordinates.

Please refer to the wiki for details on using this class member.

Getter:: Gets the bounding box
Type:: tuple

property cpsize

Number of control points in all parametric directions.

Note

This is an expert property for getting and setting control point size(s) of the geometry.

Please refer to the wiki for details on using this class member.

Getter:: Gets the number of control points
Setter:: Sets the number of control points
Type:: list

property ctrlpts

Control points.

Please refer to the wiki for details on using this class member.

Getter:: Gets the control points
Setter:: Sets the control points
Type:: list

property ctrlpts_size

Total number of control points.

Getter:: Gets the total number of control points
Type:: int

property data

Returns a dict which contains the geometry data.

Please refer to the wiki for details on using this class member.

property degree

Degree.

Please refer to the wiki for details on using this class member.

Getter:: Gets the degree
Setter:: Sets the degree
Type:: int

property delta

Evaluation delta.

Evaluation delta corresponds to the step size while evaluate function iterates on the knot vector to generate curve points. Decreasing step size results in generation of more curve points. Therefore; smaller the delta value, smoother the curve.

The following figure illustrates the working principles of the delta property:

$\left[{{u_{start}},{u_{start}} + \delta ,({u_{start}} + \delta ) + \delta , \ldots ,{u_{end}}} \right]$

Please refer to the wiki for details on using this class member.

Getter:: Gets the delta value
Setter:: Sets the delta value
Type:: float

abstractmethod derivatives(u, order, **kwargs)

Evaluates the derivatives of the curve at parameter u.

Note

This is an abstract method and it must be implemented in the subclass.

Parameters:

u (float) – parameter (u)
order (int) – derivative order

property dimension

Spatial dimension.

Spatial dimension will be automatically estimated from the first element of the control points array.

Please refer to the wiki for details on using this class member.

Getter:: Gets the spatial dimension, e.g. 2D, 3D, etc.
Type:: int

property domain

Domain.

Domain is determined using the knot vector(s).

Getter:: Gets the domain

property evalpts

Evaluated points.

Please refer to the wiki for details on using this class member.

Getter:: Gets the coordinates of the evaluated points
Type:: list

abstractmethod evaluate(**kwargs): Evaluates the curve.

Note

This is an abstract method and it must be implemented in the subclass.

abstractmethod evaluate_list(param_list)

Evaluates the curve for an input range of parameters.

Note

This is an abstract method and it must be implemented in the subclass.

Parameters:: param_list – array of parameters

abstractmethod evaluate_single(param)

Evaluates the curve at the given parameter.

Note

This is an abstract method and it must be implemented in the subclass.

Parameters:: param – parameter (u)

property evaluator

Evaluator instance.

Evaluators allow users to use different algorithms for B-Spline and NURBS evaluations. Please see the documentation on Evaluator classes.

Please refer to the wiki for details on using this class member.

Getter:: Gets the current Evaluator instance
Setter:: Sets the Evaluator instance
Type:: evaluators.AbstractEvaluator

property id

Object ID (as an integer).

Please refer to the wiki for details on using this class member.

Getter:: Gets the object ID
Setter:: Sets the object ID
Type:: int

property knotvector

Knot vector.

The knot vector will be normalized to [0, 1] domain if the class is initialized with normalize_kv=True argument.

Please refer to the wiki for details on using this class member.

Getter:: Gets the knot vector
Setter:: Sets the knot vector
Type:: list

property name

Object name (as a string)

Please refer to the wiki for details on using this class member.

Getter:: Gets the object name
Setter:: Sets the object name
Type:: str

property opt

Dictionary for storing custom data in the current geometry object.

opt is a wrapper to a dict in key => value format, where key is string, value is any Python object. You can use opt property to store custom data inside the geometry object. For instance:

geom.opt = ["face_id", 4]  # creates "face_id" key and sets its value to an integer
geom.opt = ["contents", "data values"]  # creates "face_id" key and sets its value to a string
print(geom.opt)  # will print: {'face_id': 4, 'contents': 'data values'}

del geom.opt  # deletes the contents of the hash map
print(geom.opt)  # will print: {}

geom.opt = ["body_id", 1]  # creates "body_id" key  and sets its value to 1
geom.opt = ["body_id", 12]  # changes the value of "body_id" to 12
print(geom.opt)  # will print: {'body_id': 12}

geom.opt = ["body_id", None]  # deletes "body_id"
print(geom.opt)  # will print: {}

Please refer to the wiki for details on using this class member.

Getter:: Gets the dict
Setter:: Adds key and value pair to the dict
Deleter:: Deletes the contents of the dict

opt_get(value)

Safely query for the value from the opt property.

Parameters:: value (str) – a key in the opt property
Returns:: the corresponding value, if the key exists. None, otherwise.

property order

Order.

Defined as order = degree + 1

Please refer to the wiki for details on using this class member.

Getter:: Gets the order
Setter:: Sets the order
Type:: int

property pdimension

Parametric dimension.

Please refer to the wiki for details on using this class member.

Getter:: Gets the parametric dimension
Type:: int

property range

Domain range.

Getter:: Gets the range

property rational

Defines the rational and non-rational B-spline shapes.

Rational shapes use homogeneous coordinates which includes a weight alongside with the Cartesian coordinates. Rational B-splines are also named as NURBS (Non-uniform rational basis spline) and non-rational B-splines are sometimes named as NUBS (Non-uniform basis spline) or directly as B-splines.

Please refer to the wiki for details on using this class member.

Getter:: Returns True is the B-spline object is rational (NURBS)
Type:: bool

render(**kwargs)

Renders the curve using the visualization component

The visualization component must be set using vis property before calling this method.

Keyword Arguments:

cpcolor: sets the color of the control points polygon
evalcolor: sets the color of the curve
bboxcolor: sets the color of the bounding box
filename: saves the plot with the input name
plot: controls plot window visibility. Default: True
animate: activates animation (if supported). Default: False
extras: adds line plots to the figure. Default: None

plot argument is useful when you would like to work on the command line without any window context. If plot flag is False, this method saves the plot as an image file (.png file where possible) and disables plot window popping out. If you don’t provide a file name, the name of the image file will be pulled from the configuration class.

extras argument can be used to add extra line plots to the figure. This argument expects a list of dicts in the format described below:

[
    dict(  # line plot 1
        points=[[1, 2, 3], [4, 5, 6]],  # list of points
        name="My line Plot 1",  # name displayed on the legend
        color="red",   # color of the line plot
        size=6.5  # size of the line plot
    ),
    dict(  # line plot 2
        points=[[7, 8, 9], [10, 11, 12]],  # list of points
        name="My line Plot 2",  # name displayed on the legend
        color="navy",   # color of the line plot
        size=12.5  # size of the line plot
    )
]

Returns:: the figure object

reset(**kwargs)

Resets control points and/or evaluated points.

Keyword Arguments:

evalpts: if True, then resets evaluated points
ctrlpts if True, then resets control points

reverse(): Reverses the curve

property sample_size

Sample size.

Sample size defines the number of evaluated points to generate. It also sets the delta property.

The following figure illustrates the working principles of sample size property:

$\underbrace {\left[ {{u_{start}}, \ldots ,{u_{end}}} \right]}_{{n_{sample}}}$

Please refer to the wiki for details on using this class member.

Getter:: Gets sample size
Setter:: Sets sample size
Type:: int

set_ctrlpts(ctrlpts, *args, **kwargs)

Sets control points and checks if the data is consistent.

This method is designed to provide a consistent way to set control points whether they are weighted or not. It directly sets the control points member of the class, and therefore it doesn’t return any values. The input will be an array of coordinates. If you are working in the 3-dimensional space, then your coordinates will be an array of 3 elements representing (x, y, z) coordinates.

Parameters:: ctrlpts (list) – input control points as a list of coordinates

property type

Geometry type

Please refer to the wiki for details on using this class member.

Getter:: Gets the geometry type
Type:: str

property vis

Visualization component.

Please refer to the wiki for details on using this class member.

Getter:: Gets the visualization component
Setter:: Sets the visualization component
Type:: vis.VisAbstract

property weights

Weights.

Note

Only available for rational spline geometries. Getter return None otherwise.

Please refer to the wiki for details on using this class member.

Getter:: Gets the weights
Setter:: Sets the weights

Abstract Surface

class geomdl.abstract.Surface(**kwargs)

Bases: SplineGeometry

Abstract base class for defining spline surfaces.

Surface ABC is inherited from abc.ABCMeta class which is included in Python standard library by default. Due to differences between Python 2 and 3 on defining a metaclass, the compatibility module six is employed. Using six to set metaclass allows users to use the abstract classes in a correct way.

The abstract base classes in this module are implemented using a feature called Python Properties. This feature allows users to use some of the functions as if they are class fields. You can also consider properties as a pythonic way to set getters and setters. You will see “getter” and “setter” descriptions on the documentation of these properties.

The Surface ABC allows users to set the FindSpan function to be used in evaluations with find_span_func keyword as an input to the class constructor. NURBS-Python includes a binary and a linear search variation of the FindSpan function in the helpers module. You may also implement and use your own FindSpan function. Please see the helpers module for details.

Code segment below illustrates a possible implementation of Surface abstract base class:

from geomdl import abstract

class MySurfaceClass(abstract.Surface):
    def __init__(self, **kwargs):
    super(MySurfaceClass, self).__init__(**kwargs)
    # Add your constructor code here

    def evaluate(self, **kwargs):
        # Implement this function
        pass

    def evaluate_single(self, uv):
        # Implement this function
        pass

    def evaluate_list(self, uv_list):
        # Implement this function
        pass

    def derivatives(self, u, v, order, **kwargs):
        # Implement this function
        pass

The properties and functions defined in the abstract base class will be automatically available in the subclasses.

Keyword Arguments:

id: object ID (as integer)
precision: number of decimal places to round to. Default: 18
normalize_kv: if True, knot vector(s) will be normalized to [0,1] domain. Default: True
find_span_func: default knot span finding algorithm. Default: helpers.find_span_linear()

add_trim(trim)

Adds a trim to the surface.

A trim is a 2-dimensional curve defined on the parametric domain of the surface. Therefore, x-coordinate of the trimming curve corresponds to u parametric direction of the surfaceand y-coordinate of the trimming curve corresponds to v parametric direction of the surface.

trims uses this method to add trims to the surface.

Parameters:: trim (abstract.Geometry) – surface trimming curve

property bbox

Bounding box.

Evaluates the bounding box and returns the minimum and maximum coordinates.

Please refer to the wiki for details on using this class member.

Getter:: Gets the bounding box
Type:: tuple

property cpsize

Number of control points in all parametric directions.

Note

This is an expert property for getting and setting control point size(s) of the geometry.

Please refer to the wiki for details on using this class member.

Getter:: Gets the number of control points
Setter:: Sets the number of control points
Type:: list

property ctrlpts

1-dimensional array of control points.

Note

The v index varies first. That is, a row of v control points for the first u value is found first. Then, the row of v control points for the next u value.

Please refer to the wiki for details on using this class member.

Getter:: Gets the control points
Setter:: Sets the control points
Type:: list

property ctrlpts_size

Total number of control points.

Getter:: Gets the total number of control points
Type:: int

property ctrlpts_size_u

Number of control points for the u-direction.

Please refer to the wiki for details on using this class member.

Getter:: Gets number of control points for the u-direction
Setter:: Sets number of control points for the u-direction

property ctrlpts_size_v

Number of control points for the v-direction.

Please refer to the wiki for details on using this class member.

Getter:: Gets number of control points on the v-direction
Setter:: Sets number of control points on the v-direction

property data

Returns a dict which contains the geometry data.

Please refer to the wiki for details on using this class member.

property degree

Degree for u- and v-directions

Getter:: Gets the degree
Setter:: Sets the degree
Type:: list

property degree_u

Degree for the u-direction.

Please refer to the wiki for details on using this class member.

Getter:: Gets degree for the u-direction
Setter:: Sets degree for the u-direction
Type:: int

property degree_v

Degree for the v-direction.

Please refer to the wiki for details on using this class member.

Getter:: Gets degree for the v-direction
Setter:: Sets degree for the v-direction
Type:: int

property delta

Evaluation delta for both u- and v-directions.

Evaluation delta corresponds to the step size while evaluate() function iterates on the knot vector to generate surface points. Decreasing step size results in generation of more surface points. Therefore; smaller the delta value, smoother the surface.

Please note that delta and sample_size properties correspond to the same variable with different descriptions. Therefore, setting delta will also set sample_size.

The following figure illustrates the working principles of the delta property:

$\left[{{u_{0}},{u_{start}} + \delta ,({u_{start}} + \delta ) + \delta , \ldots ,{u_{end}}} \right]$

Please refer to the wiki for details on using this class member.

Getter:: Gets evaluation delta as a tuple of values corresponding to u- and v-directions
Setter:: Sets evaluation delta for both u- and v-directions
Type:: float

property delta_u

Evaluation delta for the u-direction.

Evaluation delta corresponds to the step size while evaluate() function iterates on the knot vector to generate surface points. Decreasing step size results in generation of more surface points. Therefore; smaller the delta value, smoother the surface.

Please note that delta_u and sample_size_u properties correspond to the same variable with different descriptions. Therefore, setting delta_u will also set sample_size_u.

Please refer to the wiki for details on using this class member.

Getter:: Gets evaluation delta for the u-direction
Setter:: Sets evaluation delta for the u-direction
Type:: float

property delta_v

Evaluation delta for the v-direction.

Evaluation delta corresponds to the step size while evaluate() function iterates on the knot vector to generate surface points. Decreasing step size results in generation of more surface points. Therefore; smaller the delta value, smoother the surface.

Please note that delta_v and sample_size_v properties correspond to the same variable with different descriptions. Therefore, setting delta_v will also set sample_size_v.

Please refer to the wiki for details on using this class member.

Getter:: Gets evaluation delta for the v-direction
Setter:: Sets evaluation delta for the v-direction
Type:: float

abstractmethod derivatives(u, v, order, **kwargs)

Evaluates the derivatives of the parametric surface at parameter (u, v).

Note

This is an abstract method and it must be implemented in the subclass.

Parameters:

u (float) – parameter on the u-direction
v (float) – parameter on the v-direction
order (int) – derivative order

property dimension

Spatial dimension.

Spatial dimension will be automatically estimated from the first element of the control points array.

Please refer to the wiki for details on using this class member.

Getter:: Gets the spatial dimension, e.g. 2D, 3D, etc.
Type:: int

property domain

Domain.

Domain is determined using the knot vector(s).

Getter:: Gets the domain

property evalpts

Evaluated points.

Please refer to the wiki for details on using this class member.

Getter:: Gets the coordinates of the evaluated points
Type:: list

abstractmethod evaluate(**kwargs): Evaluates the parametric surface.

Note

This is an abstract method and it must be implemented in the subclass.

abstractmethod evaluate_list(param_list)

Evaluates the parametric surface for an input range of (u, v) parameters.

Note

This is an abstract method and it must be implemented in the subclass.

Parameters:: param_list – array of parameters (u, v)

abstractmethod evaluate_single(param)

Evaluates the parametric surface at the given (u, v) parameter.

Note

This is an abstract method and it must be implemented in the subclass.

Parameters:: param – parameter (u, v)

property evaluator

Evaluator instance.

Evaluators allow users to use different algorithms for B-Spline and NURBS evaluations. Please see the documentation on Evaluator classes.

Please refer to the wiki for details on using this class member.

Getter:: Gets the current Evaluator instance
Setter:: Sets the Evaluator instance
Type:: evaluators.AbstractEvaluator

property faces

Faces (triangles, quads, etc.) generated by the tessellation operation.

If the tessellation component is set to None, the result will be an empty list.

Getter:: Gets the faces

property id

Object ID (as an integer).

Please refer to the wiki for details on using this class member.

Getter:: Gets the object ID
Setter:: Sets the object ID
Type:: int

property knotvector

Knot vector for u- and v-directions

Getter:: Gets the knot vector
Setter:: Sets the knot vector
Type:: list

property knotvector_u

Knot vector for the u-direction.

The knot vector will be normalized to [0, 1] domain if the class is initialized with normalize_kv=True argument.

Please refer to the wiki for details on using this class member.

Getter:: Gets knot vector for the u-direction
Setter:: Sets knot vector for the u-direction
Type:: list

property knotvector_v

Knot vector for the v-direction.

The knot vector will be normalized to [0, 1] domain if the class is initialized with normalize_kv=True argument.

Please refer to the wiki for details on using this class member.

Getter:: Gets knot vector for the v-direction
Setter:: Sets knot vector for the v-direction
Type:: list

property name

Object name (as a string)

Please refer to the wiki for details on using this class member.

Getter:: Gets the object name
Setter:: Sets the object name
Type:: str

property opt

Dictionary for storing custom data in the current geometry object.

opt is a wrapper to a dict in key => value format, where key is string, value is any Python object. You can use opt property to store custom data inside the geometry object. For instance:

geom.opt = ["face_id", 4]  # creates "face_id" key and sets its value to an integer
geom.opt = ["contents", "data values"]  # creates "face_id" key and sets its value to a string
print(geom.opt)  # will print: {'face_id': 4, 'contents': 'data values'}

del geom.opt  # deletes the contents of the hash map
print(geom.opt)  # will print: {}

geom.opt = ["body_id", 1]  # creates "body_id" key  and sets its value to 1
geom.opt = ["body_id", 12]  # changes the value of "body_id" to 12
print(geom.opt)  # will print: {'body_id': 12}

geom.opt = ["body_id", None]  # deletes "body_id"
print(geom.opt)  # will print: {}

Please refer to the wiki for details on using this class member.

Getter:: Gets the dict
Setter:: Adds key and value pair to the dict
Deleter:: Deletes the contents of the dict

opt_get(value)

Safely query for the value from the opt property.

Parameters:: value (str) – a key in the opt property
Returns:: the corresponding value, if the key exists. None, otherwise.

property order_u

Order for the u-direction.

Defined as order = degree + 1

Please refer to the wiki for details on using this class member.

Getter:: Gets order for the u-direction
Setter:: Sets order for the u-direction
Type:: int

property order_v

Order for the v-direction.

Defined as order = degree + 1

Please refer to the wiki for details on using this class member.

Getter:: Gets surface order for the v-direction
Setter:: Sets surface order for the v-direction
Type:: int

property pdimension

Parametric dimension.

Please refer to the wiki for details on using this class member.

Getter:: Gets the parametric dimension
Type:: int

property range

Domain range.

Getter:: Gets the range

property rational

Defines the rational and non-rational B-spline shapes.

Rational shapes use homogeneous coordinates which includes a weight alongside with the Cartesian coordinates. Rational B-splines are also named as NURBS (Non-uniform rational basis spline) and non-rational B-splines are sometimes named as NUBS (Non-uniform basis spline) or directly as B-splines.

Please refer to the wiki for details on using this class member.

Getter:: Returns True is the B-spline object is rational (NURBS)
Type:: bool

render(**kwargs)

Renders the surface using the visualization component.

The visualization component must be set using vis property before calling this method.

Keyword Arguments:

cpcolor: sets the color of the control points grid
evalcolor: sets the color of the surface
trimcolor: sets the color of the trim curves
filename: saves the plot with the input name
plot: controls plot window visibility. Default: True
animate: activates animation (if supported). Default: False
extras: adds line plots to the figure. Default: None
colormap: sets the colormap of the surface

The plot argument is useful when you would like to work on the command line without any window context. If plot flag is False, this method saves the plot as an image file (.png file where possible) and disables plot window popping out. If you don’t provide a file name, the name of the image file will be pulled from the configuration class.

extras argument can be used to add extra line plots to the figure. This argument expects a list of dicts in the format described below:

[
    dict(  # line plot 1
        points=[[1, 2, 3], [4, 5, 6]],  # list of points
        name="My line Plot 1",  # name displayed on the legend
        color="red",   # color of the line plot
        size=6.5  # size of the line plot
    ),
    dict(  # line plot 2
        points=[[7, 8, 9], [10, 11, 12]],  # list of points
        name="My line Plot 2",  # name displayed on the legend
        color="navy",   # color of the line plot
        size=12.5  # size of the line plot
    )
]

Please note that colormap argument can only work with visualization classes that support colormaps. As an example, please see VisMPL.VisSurfTriangle() class documentation. This method expects a single colormap input.

Returns:: the figure object

reset(**kwargs)

Resets control points and/or evaluated points.

Keyword Arguments:

evalpts: if True, then resets evaluated points
ctrlpts if True, then resets control points

property sample_size

Sample size for both u- and v-directions.

Sample size defines the number of surface points to generate. It also sets the delta property.

The following figure illustrates the working principles of sample size property:

$\underbrace {\left[ {{u_{start}}, \ldots ,{u_{end}}} \right]}_{{n_{sample}}}$

Please refer to the wiki for details on using this class member.

Getter:: Gets sample size as a tuple of values corresponding to u- and v-directions
Setter:: Sets sample size for both u- and v-directions
Type:: int

property sample_size_u

Sample size for the u-direction.

Sample size defines the number of surface points to generate. It also sets the delta_u property.

Please refer to the wiki for details on using this class member.

Getter:: Gets sample size for the u-direction
Setter:: Sets sample size for the u-direction
Type:: int

property sample_size_v

Sample size for the v-direction.

Sample size defines the number of surface points to generate. It also sets the delta_v property.

Please refer to the wiki for details on using this class member.

Getter:: Gets sample size for the v-direction
Setter:: Sets sample size for the v-direction
Type:: int

set_ctrlpts(ctrlpts, *args, **kwargs)

Sets the control points and checks if the data is consistent.

This method is designed to provide a consistent way to set control points whether they are weighted or not. It directly sets the control points member of the class, and therefore it doesn’t return any values. The input will be an array of coordinates. If you are working in the 3-dimensional space, then your coordinates will be an array of 3 elements representing (x, y, z) coordinates.

Note

The v index varies first. That is, a row of v control points for the first u value is found first. Then, the row of v control points for the next u value.

Parameters:

ctrlpts (list) – input control points as a list of coordinates
args (tuple[int, int]) – number of control points corresponding to each parametric dimension

tessellate(**kwargs)

Tessellates the surface.

Keyword arguments are directly passed to the tessellation component.

property tessellator

Tessellation component.

Please refer to the wiki for details on using this class member.

Getter:: Gets the tessellation component
Setter:: Sets the tessellation component

property trims

Curves for trimming the surface.

Surface trims are 2-dimensional curves which are introduced on the parametric space of the surfaces. Trim curves can be a spline curve, an analytic curve or a 2-dimensional freeform shape. To visualize the trimmed surfaces, you need to use a tessellator that supports trimming. The following code snippet illustrates changing the default surface tessellator to the trimmed surface tessellator, tessellate.TrimTessellate.

from geomdl import tessellate

# Assuming that "surf" variable stores the surface instance
surf.tessellator = tessellate.TrimTessellate()

In addition, using trims initialization argument of the visualization classes, trim curves can be visualized together with their underlying surfaces. Please refer to the visualization configuration class initialization arguments for more details.

Please refer to the wiki for details on using this class member.

Getter:: Gets the array of trim curves
Setter:: Sets the array of trim curves

property type

Geometry type

Please refer to the wiki for details on using this class member.

Getter:: Gets the geometry type
Type:: str

property vertices

Vertices generated by the tessellation operation.

If the tessellation component is set to None, the result will be an empty list.

Getter:: Gets the vertices

property vis

Visualization component.

Please refer to the wiki for details on using this class member.

Getter:: Gets the visualization component
Setter:: Sets the visualization component
Type:: vis.VisAbstract

property weights

Weights.

Note

Only available for rational spline geometries. Getter return None otherwise.

Please refer to the wiki for details on using this class member.

Getter:: Gets the weights
Setter:: Sets the weights

Abstract Volume

class geomdl.abstract.Volume(**kwargs)

Bases: SplineGeometry

Abstract base class for defining spline volumes.

Volume ABC is inherited from abc.ABCMeta class which is included in Python standard library by default. Due to differences between Python 2 and 3 on defining a metaclass, the compatibility module six is employed. Using six to set metaclass allows users to use the abstract classes in a correct way.

The abstract base classes in this module are implemented using a feature called Python Properties. This feature allows users to use some of the functions as if they are class fields. You can also consider properties as a pythonic way to set getters and setters. You will see “getter” and “setter” descriptions on the documentation of these properties.

The Volume ABC allows users to set the FindSpan function to be used in evaluations with find_span_func keyword as an input to the class constructor. NURBS-Python includes a binary and a linear search variation of the FindSpan function in the helpers module. You may also implement and use your own FindSpan function. Please see the helpers module for details.

Code segment below illustrates a possible implementation of Volume abstract base class:

from geomdl import abstract

class MyVolumeClass(abstract.Volume):
    def __init__(self, **kwargs):
    super(MyVolumeClass, self).__init__(**kwargs)
    # Add your constructor code here

    def evaluate(self, **kwargs):
        # Implement this function
        pass

    def evaluate_single(self, uvw):
        # Implement this function
        pass

    def evaluate_list(self, uvw_list):
        # Implement this function
        pass

The properties and functions defined in the abstract base class will be automatically available in the subclasses.

Keyword Arguments:

id: object ID (as integer)
precision: number of decimal places to round to. Default: 18
normalize_kv: if True, knot vector(s) will be normalized to [0,1] domain. Default: True
find_span_func: default knot span finding algorithm. Default: helpers.find_span_linear()

add_trim(trim)

Adds a trim to the volume.

trims uses this method to add trims to the volume.

Parameters:: trim (abstract.Surface) – trimming surface

property bbox

Bounding box.

Evaluates the bounding box and returns the minimum and maximum coordinates.

Please refer to the wiki for details on using this class member.

Getter:: Gets the bounding box
Type:: tuple

property cpsize

Number of control points in all parametric directions.

Note

This is an expert property for getting and setting control point size(s) of the geometry.

Please refer to the wiki for details on using this class member.

Getter:: Gets the number of control points
Setter:: Sets the number of control points
Type:: list

property ctrlpts

1-dimensional array of control points.

Please refer to the wiki for details on using this class member.

Getter:: Gets the control points
Setter:: Sets the control points
Type:: list

property ctrlpts_size

Total number of control points.

Getter:: Gets the total number of control points
Type:: int

property ctrlpts_size_u

Number of control points for the u-direction.

Please refer to the wiki for details on using this class member.

Getter:: Gets number of control points for the u-direction
Setter:: Sets number of control points for the u-direction

property ctrlpts_size_v

Number of control points for the v-direction.

Please refer to the wiki for details on using this class member.

Getter:: Gets number of control points for the v-direction
Setter:: Sets number of control points for the v-direction

property ctrlpts_size_w

Number of control points for the w-direction.

Please refer to the wiki for details on using this class member.

Getter:: Gets number of control points for the w-direction
Setter:: Sets number of control points for the w-direction

property data

Returns a dict which contains the geometry data.

Please refer to the wiki for details on using this class member.

property degree

Degree for u-, v- and w-directions

Getter:: Gets the degree
Setter:: Sets the degree
Type:: list

property degree_u

Degree for the u-direction.

Please refer to the wiki for details on using this class member.

Getter:: Gets degree for the u-direction
Setter:: Sets degree for the u-direction
Type:: int

property degree_v

Degree for the v-direction.

Please refer to the wiki for details on using this class member.

Getter:: Gets degree for the v-direction
Setter:: Sets degree for the v-direction
Type:: int

property degree_w

Degree for the w-direction.

Please refer to the wiki for details on using this class member.

Getter:: Gets degree for the w-direction
Setter:: Sets degree for the w-direction
Type:: int

property delta

Evaluation delta for u-, v- and w-directions.

Evaluation delta corresponds to the step size while evaluate() function iterates on the knot vector to generate surface points. Decreasing step size results in generation of more surface points. Therefore; smaller the delta value, smoother the surface.

Please note that delta and sample_size properties correspond to the same variable with different descriptions. Therefore, setting delta will also set sample_size.

The following figure illustrates the working principles of the delta property:

$\left[{{u_{0}},{u_{start}} + \delta ,({u_{start}} + \delta ) + \delta , \ldots ,{u_{end}}} \right]$

Please refer to the wiki for details on using this class member.

Getter:: Gets evaluation delta as a tuple of values corresponding to u-, v- and w-directions
Setter:: Sets evaluation delta for u-, v- and w-directions
Type:: float

property delta_u

Evaluation delta for the u-direction.

Evaluation delta corresponds to the step size while evaluate() function iterates on the knot vector to generate surface points. Decreasing step size results in generation of more surface points. Therefore; smaller the delta value, smoother the surface.

Please note that delta_u and sample_size_u properties correspond to the same variable with different descriptions. Therefore, setting delta_u will also set sample_size_u.

Please refer to the wiki for details on using this class member.

Getter:: Gets evaluation delta for the u-direction
Setter:: Sets evaluation delta for the u-direction
Type:: float

property delta_v

Evaluation delta for the v-direction.

Evaluation delta corresponds to the step size while evaluate() function iterates on the knot vector to generate surface points. Decreasing step size results in generation of more surface points. Therefore; smaller the delta value, smoother the surface.

Please note that delta_v and sample_size_v properties correspond to the same variable with different descriptions. Therefore, setting delta_v will also set sample_size_v.

Please refer to the wiki for details on using this class member.

Getter:: Gets evaluation delta for the v-direction
Setter:: Sets evaluation delta for the v-direction
Type:: float

property delta_w

Evaluation delta for the w-direction.

Evaluation delta corresponds to the step size while evaluate() function iterates on the knot vector to generate surface points. Decreasing step size results in generation of more surface points. Therefore; smaller the delta value, smoother the surface.

Please note that delta_w and sample_size_w properties correspond to the same variable with different descriptions. Therefore, setting delta_w will also set sample_size_w.

Please refer to the wiki for details on using this class member.

Getter:: Gets evaluation delta for the w-direction
Setter:: Sets evaluation delta for the w-direction
Type:: float

property dimension

Spatial dimension.

Spatial dimension will be automatically estimated from the first element of the control points array.

Please refer to the wiki for details on using this class member.

Getter:: Gets the spatial dimension, e.g. 2D, 3D, etc.
Type:: int

property domain

Domain.

Domain is determined using the knot vector(s).

Getter:: Gets the domain

property evalpts

Evaluated points.

Please refer to the wiki for details on using this class member.

Getter:: Gets the coordinates of the evaluated points
Type:: list

abstractmethod evaluate(**kwargs): Evaluates the parametric volume.

Note

This is an abstract method and it must be implemented in the subclass.

abstractmethod evaluate_list(param_list)

Evaluates the parametric volume for an input range of (u, v, w) parameter pairs.

Note

This is an abstract method and it must be implemented in the subclass.

Parameters:: param_list – array of parameter pairs (u, v, w)

abstractmethod evaluate_single(param)

Evaluates the parametric surface at the given (u, v, w) parameter.

Note

This is an abstract method and it must be implemented in the subclass.

Parameters:: param – parameter pair (u, v, w)

property evaluator

Evaluator instance.

Evaluators allow users to use different algorithms for B-Spline and NURBS evaluations. Please see the documentation on Evaluator classes.

Please refer to the wiki for details on using this class member.

Getter:: Gets the current Evaluator instance
Setter:: Sets the Evaluator instance
Type:: evaluators.AbstractEvaluator

property id

Object ID (as an integer).

Please refer to the wiki for details on using this class member.

Getter:: Gets the object ID
Setter:: Sets the object ID
Type:: int

property knotvector

Knot vector for u-, v- and w-directions

Getter:: Gets the knot vector
Setter:: Sets the knot vector
Type:: list

property knotvector_u

Knot vector for the u-direction.

The knot vector will be normalized to [0, 1] domain if the class is initialized with normalize_kv=True argument.

Please refer to the wiki for details on using this class member.

Getter:: Gets knot vector for the u-direction
Setter:: Sets knot vector for the u-direction
Type:: list

property knotvector_v

Knot vector for the v-direction.

The knot vector will be normalized to [0, 1] domain if the class is initialized with normalize_kv=True argument.

Please refer to the wiki for details on using this class member.

Getter:: Gets knot vector for the v-direction
Setter:: Sets knot vector for the v-direction
Type:: list

property knotvector_w

Knot vector for the w-direction.

The knot vector will be normalized to [0, 1] domain if the class is initialized with normalize_kv=True argument.

Please refer to the wiki for details on using this class member.

Getter:: Gets knot vector for the w-direction
Setter:: Sets knot vector for the w-direction
Type:: list

property name

Object name (as a string)

Please refer to the wiki for details on using this class member.

Getter:: Gets the object name
Setter:: Sets the object name
Type:: str

property opt

Dictionary for storing custom data in the current geometry object.

opt is a wrapper to a dict in key => value format, where key is string, value is any Python object. You can use opt property to store custom data inside the geometry object. For instance:

geom.opt = ["face_id", 4]  # creates "face_id" key and sets its value to an integer
geom.opt = ["contents", "data values"]  # creates "face_id" key and sets its value to a string
print(geom.opt)  # will print: {'face_id': 4, 'contents': 'data values'}

del geom.opt  # deletes the contents of the hash map
print(geom.opt)  # will print: {}

geom.opt = ["body_id", 1]  # creates "body_id" key  and sets its value to 1
geom.opt = ["body_id", 12]  # changes the value of "body_id" to 12
print(geom.opt)  # will print: {'body_id': 12}

geom.opt = ["body_id", None]  # deletes "body_id"
print(geom.opt)  # will print: {}

Please refer to the wiki for details on using this class member.

Getter:: Gets the dict
Setter:: Adds key and value pair to the dict
Deleter:: Deletes the contents of the dict

opt_get(value)

Safely query for the value from the opt property.

Parameters:: value (str) – a key in the opt property
Returns:: the corresponding value, if the key exists. None, otherwise.

property order_u

Order for the u-direction.

Defined as order = degree + 1

Please refer to the wiki for details on using this class member.

Getter:: Gets the surface order for u-direction
Setter:: Sets the surface order for u-direction
Type:: int

property order_v

Order for the v-direction.

Defined as order = degree + 1

Please refer to the wiki for details on using this class member.

Getter:: Gets the surface order for v-direction
Setter:: Sets the surface order for v-direction
Type:: int

property order_w

Order for the w-direction.

Defined as order = degree + 1

Please refer to the wiki for details on using this class member.

Getter:: Gets the surface order for v-direction
Setter:: Sets the surface order for v-direction
Type:: int

property pdimension

Parametric dimension.

Please refer to the wiki for details on using this class member.

Getter:: Gets the parametric dimension
Type:: int

property range

Domain range.

Getter:: Gets the range

property rational

Defines the rational and non-rational B-spline shapes.

Rational shapes use homogeneous coordinates which includes a weight alongside with the Cartesian coordinates. Rational B-splines are also named as NURBS (Non-uniform rational basis spline) and non-rational B-splines are sometimes named as NUBS (Non-uniform basis spline) or directly as B-splines.

Please refer to the wiki for details on using this class member.

Getter:: Returns True is the B-spline object is rational (NURBS)
Type:: bool

render(**kwargs)

Renders the volume using the visualization component.

The visualization component must be set using vis property before calling this method.

Keyword Arguments:

cpcolor: sets the color of the control points
evalcolor: sets the color of the volume
filename: saves the plot with the input name
plot: controls plot window visibility. Default: True
animate: activates animation (if supported). Default: False
grid_size: grid size for voxelization. Default: (8, 8, 8)
use_cubes: use cube voxels instead of cuboid ones. Default: False
num_procs: number of concurrent processes for voxelization. Default: 1

The plot argument is useful when you would like to work on the command line without any window context. If plot flag is False, this method saves the plot as an image file (.png file where possible) and disables plot window popping out. If you don’t provide a file name, the name of the image file will be pulled from the configuration class.

extras argument can be used to add extra line plots to the figure. This argument expects a list of dicts in the format described below:

[
    dict(  # line plot 1
        points=[[1, 2, 3], [4, 5, 6]],  # list of points
        name="My line Plot 1",  # name displayed on the legend
        color="red",   # color of the line plot
        size=6.5  # size of the line plot
    ),
    dict(  # line plot 2
        points=[[7, 8, 9], [10, 11, 12]],  # list of points
        name="My line Plot 2",  # name displayed on the legend
        color="navy",   # color of the line plot
        size=12.5  # size of the line plot
    )
]

Returns:: the figure object

reset(**kwargs)

Resets control points and/or evaluated points.

Keyword Arguments:

evalpts: if True, then resets evaluated points
ctrlpts if True, then resets control points

property sample_size

Sample size for both u- and v-directions.

Sample size defines the number of surface points to generate. It also sets the delta property.

The following figure illustrates the working principles of sample size property:

$\underbrace {\left[ {{u_{start}}, \ldots ,{u_{end}}} \right]}_{{n_{sample}}}$

Please refer to the wiki for details on using this class member.

Getter:: Gets sample size as a tuple of values corresponding to u-, v- and w-directions
Setter:: Sets sample size value for both u-, v- and w-directions
Type:: int

property sample_size_u

Sample size for the u-direction.

Sample size defines the number of evaluated points to generate. It also sets the delta_u property.

Please refer to the wiki for details on using this class member.

Getter:: Gets sample size for the u-direction
Setter:: Sets sample size for the u-direction
Type:: int

property sample_size_v

Sample size for the v-direction.

Sample size defines the number of evaluated points to generate. It also sets the delta_v property.

Please refer to the wiki for details on using this class member.

Getter:: Gets sample size for the v-direction
Setter:: Sets sample size for the v-direction
Type:: int

property sample_size_w

Sample size for the w-direction.

Sample size defines the number of evaluated points to generate. It also sets the delta_w property.

Please refer to the wiki for details on using this class member.

Getter:: Gets sample size for the w-direction
Setter:: Sets sample size for the w-direction
Type:: int

set_ctrlpts(ctrlpts, *args, **kwargs)

Sets the control points and checks if the data is consistent.

This method is designed to provide a consistent way to set control points whether they are weighted or not. It directly sets the control points member of the class, and therefore it doesn’t return any values. The input will be an array of coordinates. If you are working in the 3-dimensional space, then your coordinates will be an array of 3 elements representing (x, y, z) coordinates.

Parameters:

ctrlpts (list) – input control points as a list of coordinates
args (tuple[int, int, int]) – number of control points corresponding to each parametric dimension

property trims

Trimming surfaces.

Please refer to the wiki for details on using this class member.

Getter:: Gets the array of trim surfaces
Setter:: Sets the array of trim surfaces

property type

Geometry type

Please refer to the wiki for details on using this class member.

Getter:: Gets the geometry type
Type:: str

property vis

Visualization component.

Please refer to the wiki for details on using this class member.

Getter:: Gets the visualization component
Setter:: Sets the visualization component
Type:: vis.VisAbstract

property weights

Weights.

Note

Only available for rational spline geometries. Getter return None otherwise.

Please refer to the wiki for details on using this class member.

Getter:: Gets the weights
Setter:: Sets the weights

Low Level API

The following classes provide the low level API for the geometry abstract base.

GeomdlBase
Geometry
SplineGeometry

Geometry abstract base class can be used for implementation of any geometry object, whereas SplineGeometry abstract base class is designed specifically for spline geometries, including basis splines.

class geomdl.abstract.GeomdlBase(**kwargs)

Bases: object

Abstract base class for defining geomdl objects.

This class provides the following properties:

type
id
name
dimension
opt

Keyword Arguments:

id: object ID (as integer)
precision: number of decimal places to round to. Default: 18

property dimension

Spatial dimension.

Please refer to the wiki for details on using this class member.

Getter:: Gets the spatial dimension, e.g. 2D, 3D, etc.
Type:: int

property id

Object ID (as an integer).

Please refer to the wiki for details on using this class member.

Getter:: Gets the object ID
Setter:: Sets the object ID
Type:: int

property name

Object name (as a string)

Please refer to the wiki for details on using this class member.

Getter:: Gets the object name
Setter:: Sets the object name
Type:: str

property opt

Dictionary for storing custom data in the current geometry object.

opt is a wrapper to a dict in key => value format, where key is string, value is any Python object. You can use opt property to store custom data inside the geometry object. For instance:

geom.opt = ["face_id", 4]  # creates "face_id" key and sets its value to an integer
geom.opt = ["contents", "data values"]  # creates "face_id" key and sets its value to a string
print(geom.opt)  # will print: {'face_id': 4, 'contents': 'data values'}

del geom.opt  # deletes the contents of the hash map
print(geom.opt)  # will print: {}

geom.opt = ["body_id", 1]  # creates "body_id" key  and sets its value to 1
geom.opt = ["body_id", 12]  # changes the value of "body_id" to 12
print(geom.opt)  # will print: {'body_id': 12}

geom.opt = ["body_id", None]  # deletes "body_id"
print(geom.opt)  # will print: {}

Please refer to the wiki for details on using this class member.

Getter:: Gets the dict
Setter:: Adds key and value pair to the dict
Deleter:: Deletes the contents of the dict

opt_get(value)

Safely query for the value from the opt property.

Parameters:: value (str) – a key in the opt property
Returns:: the corresponding value, if the key exists. None, otherwise.

property type

Geometry type

Please refer to the wiki for details on using this class member.

Getter:: Gets the geometry type
Type:: str

class geomdl.abstract.Geometry(**kwargs)

Bases: GeomdlBase

Abstract base class for defining geometry objects.

This class provides the following properties:

type
id
name
dimension
evalpts
opt

Keyword Arguments:

id: object ID (as integer)
precision: number of decimal places to round to. Default: 18

property dimension

Spatial dimension.

Please refer to the wiki for details on using this class member.

Getter:: Gets the spatial dimension, e.g. 2D, 3D, etc.
Type:: int

property evalpts

Evaluated points.

Please refer to the wiki for details on using this class member.

Getter:: Gets the coordinates of the evaluated points
Type:: list

abstractmethod evaluate(**kwargs): Abstract method for the implementation of evaluation algorithm.

Note

This is an abstract method and it must be implemented in the subclass.

property id

Object ID (as an integer).

Please refer to the wiki for details on using this class member.

Getter:: Gets the object ID
Setter:: Sets the object ID
Type:: int

property name

Object name (as a string)

Please refer to the wiki for details on using this class member.

Getter:: Gets the object name
Setter:: Sets the object name
Type:: str

property opt

Dictionary for storing custom data in the current geometry object.

opt is a wrapper to a dict in key => value format, where key is string, value is any Python object. You can use opt property to store custom data inside the geometry object. For instance:

geom.opt = ["face_id", 4]  # creates "face_id" key and sets its value to an integer
geom.opt = ["contents", "data values"]  # creates "face_id" key and sets its value to a string
print(geom.opt)  # will print: {'face_id': 4, 'contents': 'data values'}

del geom.opt  # deletes the contents of the hash map
print(geom.opt)  # will print: {}

geom.opt = ["body_id", 1]  # creates "body_id" key  and sets its value to 1
geom.opt = ["body_id", 12]  # changes the value of "body_id" to 12
print(geom.opt)  # will print: {'body_id': 12}

geom.opt = ["body_id", None]  # deletes "body_id"
print(geom.opt)  # will print: {}

Please refer to the wiki for details on using this class member.

Getter:: Gets the dict
Setter:: Adds key and value pair to the dict
Deleter:: Deletes the contents of the dict

opt_get(value)

Safely query for the value from the opt property.

Parameters:: value (str) – a key in the opt property
Returns:: the corresponding value, if the key exists. None, otherwise.

property type

Geometry type

Please refer to the wiki for details on using this class member.

Getter:: Gets the geometry type
Type:: str

class geomdl.abstract.SplineGeometry(**kwargs)

Bases: Geometry

Abstract base class for defining spline geometry objects.

This class provides the following properties:

type = spline
id
name
rational
dimension
pdimension
degree
knotvector
ctrlpts
ctrlpts_size
weights (for completeness with the rational spline implementations)
evalpts
bbox
evaluator
vis
opt

Keyword Arguments:

id: object ID (as integer)
precision: number of decimal places to round to. Default: 18
normalize_kv: if True, knot vector(s) will be normalized to [0,1] domain. Default: True
find_span_func: default knot span finding algorithm. Default: helpers.find_span_linear()

property bbox

Bounding box.

Evaluates the bounding box and returns the minimum and maximum coordinates.

Please refer to the wiki for details on using this class member.

Getter:: Gets the bounding box
Type:: tuple

property cpsize

Number of control points in all parametric directions.

Note

This is an expert property for getting and setting control point size(s) of the geometry.

Please refer to the wiki for details on using this class member.

Getter:: Gets the number of control points
Setter:: Sets the number of control points
Type:: list

property ctrlpts

Control points.

Please refer to the wiki for details on using this class member.

Getter:: Gets the control points
Setter:: Sets the control points
Type:: list

property ctrlpts_size

Total number of control points.

Getter:: Gets the total number of control points
Type:: int

property degree

Degree

Note

This is an expert property for getting and setting the degree(s) of the geometry.

Please refer to the wiki for details on using this class member.

Getter:: Gets the degree
Setter:: Sets the degree
Type:: list

property dimension

Spatial dimension.

Spatial dimension will be automatically estimated from the first element of the control points array.

Please refer to the wiki for details on using this class member.

Getter:: Gets the spatial dimension, e.g. 2D, 3D, etc.
Type:: int

property domain

Domain.

Domain is determined using the knot vector(s).

Getter:: Gets the domain

property evalpts

Evaluated points.

Please refer to the wiki for details on using this class member.

Getter:: Gets the coordinates of the evaluated points
Type:: list

abstractmethod evaluate(**kwargs): Abstract method for the implementation of evaluation algorithm.

Note

This is an abstract method and it must be implemented in the subclass.

property evaluator

Evaluator instance.

Evaluators allow users to use different algorithms for B-Spline and NURBS evaluations. Please see the documentation on Evaluator classes.

Please refer to the wiki for details on using this class member.

Getter:: Gets the current Evaluator instance
Setter:: Sets the Evaluator instance
Type:: evaluators.AbstractEvaluator

property id

Object ID (as an integer).

Please refer to the wiki for details on using this class member.

Getter:: Gets the object ID
Setter:: Sets the object ID
Type:: int

property knotvector

Knot vector

Note

This is an expert property for getting and setting the knot vector(s) of the geometry.

Please refer to the wiki for details on using this class member.

Getter:: Gets the knot vector
Setter:: Sets the knot vector
Type:: list

property name

Object name (as a string)

Please refer to the wiki for details on using this class member.

Getter:: Gets the object name
Setter:: Sets the object name
Type:: str

property opt

Dictionary for storing custom data in the current geometry object.

opt is a wrapper to a dict in key => value format, where key is string, value is any Python object. You can use opt property to store custom data inside the geometry object. For instance:

geom.opt = ["face_id", 4]  # creates "face_id" key and sets its value to an integer
geom.opt = ["contents", "data values"]  # creates "face_id" key and sets its value to a string
print(geom.opt)  # will print: {'face_id': 4, 'contents': 'data values'}

del geom.opt  # deletes the contents of the hash map
print(geom.opt)  # will print: {}

geom.opt = ["body_id", 1]  # creates "body_id" key  and sets its value to 1
geom.opt = ["body_id", 12]  # changes the value of "body_id" to 12
print(geom.opt)  # will print: {'body_id': 12}

geom.opt = ["body_id", None]  # deletes "body_id"
print(geom.opt)  # will print: {}

Please refer to the wiki for details on using this class member.

Getter:: Gets the dict
Setter:: Adds key and value pair to the dict
Deleter:: Deletes the contents of the dict

opt_get(value)

Safely query for the value from the opt property.

Parameters:: value (str) – a key in the opt property
Returns:: the corresponding value, if the key exists. None, otherwise.

property pdimension

Parametric dimension.

Please refer to the wiki for details on using this class member.

Getter:: Gets the parametric dimension
Type:: int

property range

Domain range.

Getter:: Gets the range

property rational

Defines the rational and non-rational B-spline shapes.

Rational shapes use homogeneous coordinates which includes a weight alongside with the Cartesian coordinates. Rational B-splines are also named as NURBS (Non-uniform rational basis spline) and non-rational B-splines are sometimes named as NUBS (Non-uniform basis spline) or directly as B-splines.

Please refer to the wiki for details on using this class member.

Getter:: Returns True is the B-spline object is rational (NURBS)
Type:: bool

abstractmethod render(**kwargs): Abstract method for spline rendering and visualization.

Note

This is an abstract method and it must be implemented in the subclass.

set_ctrlpts(ctrlpts, *args, **kwargs)

Sets control points and checks if the data is consistent.

This method is designed to provide a consistent way to set control points whether they are weighted or not. It directly sets the control points member of the class, and therefore it doesn’t return any values. The input will be an array of coordinates. If you are working in the 3-dimensional space, then your coordinates will be an array of 3 elements representing (x, y, z) coordinates.

Keyword Arguments:

array_init: initializes the control points array in the instance
array_check_for: defines the types for input validation
callback: defines the callback function for processing input points
dimension: defines the spatial dimension of the input points

Parameters:

ctrlpts (list) – input control points as a list of coordinates
args (tuple) – number of control points corresponding to each parametric dimension

property type

Geometry type

Please refer to the wiki for details on using this class member.

Getter:: Gets the geometry type
Type:: str

property vis

Visualization component.

Please refer to the wiki for details on using this class member.

Getter:: Gets the visualization component
Setter:: Sets the visualization component
Type:: vis.VisAbstract

property weights

Weights.

Note

Only available for rational spline geometries. Getter return None otherwise.

Please refer to the wiki for details on using this class member.

Getter:: Gets the weights
Setter:: Sets the weights