Geometry Types¶
polymesh
¶
Polygonal mesh geometry. A polygonal mesh is formed of points, a vertex list (defining vertices) and start index list (defining faces). Additional information, such as normals and arbitrary data, can also be defined.
Type 
Attribute 
Description 



List of perpoint normals. 


List of points. The geometry points are unique floating point positions in object space coordinates (x, y, z). Each point is only stored once but it may be indexed many times by a particular vertex. 


A list of indices defining the faces of a mesh. For example,
consider a cube. A cube has a
The indices for each polygon N are from 


Describes the vertex data of a mesh. There is a vertex at each edge
intersection. The value of the 


List of perface vertex normals. 


List of texture coordinates (per vertex, non facevarying) 
subdmesh
¶
Subdivision surfaces geometry. Subdivision surfaces (Subds) are similarly structured to polygonal meshes.
Note
This section is under construction.
Type 
Attribute 
Description 



























See polymesh. 


See polymesh. 


See polymesh. 
pointcloud
¶
Point cloud geometry. A point cloud is the simplest form of geometry and only requires point data to be specified.
Type 
Attribute 
Description 



See polymesh. 
nurbspatch
¶
NURBS patch geometry. NURBS patches are a special type of geometry, quite different from conventional mesh types. A NURBS curve is defined by its order, a set of weighted control points and a knot vector.
Type 
Attribute 
Description 



The size. 


List of control points and their weights, in the order: x y z w. 


The order. 


Parameters defining the NURBS patch. 


Knot vector, a sequence of parameter values. 


Parameters defining the NURBS patch. 
curves
¶
For creating groups of curves parented to the same transform. Curves cannot be created by the UI but can be created through the Python API.
The following XML is from a scene graph that creates 3 linear curves with 3 segments:
<attr type="GroupAttr" inheritChildren="false">
<attr type="IntAttr" name="degree" tupleSize="1">
<sample value="1 " size="1" time="0"/>
</attr>
<attr type="FloatAttr" name="knots" tupleSize="1">
<sample value="0.0 " size="1" time="0"/>
</attr>
<attr type="IntAttr" name="numVertices" tupleSize="1">
<sample value="4 4 4 " size="3" time="0"/>
</attr>
<attr type="GroupAttr" name="point" inheritChildren="false">
<attr type="FloatAttr" name="P" tupleSize="3">
<sample value="0.2 0 5 2.8 0 2.0 0.5 0 1.0 0.3 0 1.5 1.8 0
4.9 0.4 0 2.2 2.5 0 1.0 1.6 0 1.4 3.8 0 4.9
1.6 0 2.2 4.5 0 1.0 3.6 0 1.4"
size="36" time="0"/>
</attr>
</attr>
</attr>
Type 
Attribute 
Description 



An integer indicating the curve basis. This is defined as follows:
This follows the 


A float that defines the width of a curve, which is applied uniformly to each control point. 


Specifies whether curves are linear (degree = 1) or cubic (degree = 3). 


Knot vector is a sequence of parameter values. Note When splitting 


Sets the vertex stride for the curve. This is used by Katana to calculate the expected length of pointscoped arbitrary attribute arrays. 


The number of vertices in each curve. The 


List of points. The geometry points are unique floating point positions in object space coordinates (x, y, z). Each point is only stored once but it may be indexed many times by the same knot. 


List of orientations for each control point in the curve, relative to the camera. 


List of widths (diameters) of the curve at each control point. Note If both 


List of widths (diameters) of the curve if the scope is not Note If both Note If both 
locator
¶
Used only in the Viewer; ignored by the renderers.
Type 
Attribute 
Description 



See polymesh. 


See polymesh. 
sphere
¶
Builtin primitive type for a sphere, supported by some renderers.
Type 
Attribute 
Description 



The radius of the sphere. 
spheres
¶
A more efficient way of creating a group of spheres in PRMan at once. This is ignored by other renderers.
Type 
Attribute 
Description 



List of points that represent the sphere centers. 


The spheres’ radii. 


Can be used instead of 