primary_shape_geo
A modifiable hou.Geometry for the primary shape.
Functions ¶
addBlendshapeInputs(base_shape_geo, shapes, channel_names)
Adds blendshape inputs to a shape’s geometry.
This sets up the required detail attributes (blendshape_shapenames and blendshape_channels) on the base shape’s geometry.
For an existing agent shape, blendshape inputs can also be added using hou.AgentShape.addBlendshapeInputs.
base_shape_geo
A modifiable hou.Geometry for the base shape.
shapes
A hou.AgentShape sequence to add as blendshape inputs. hou.AgentShapeLibrary.addShape should be called separately to add these shapes to the shape library.
channel_names
A str sequence specifying the channel name to use for each shape.
Raises hou.InvalidSize if the length does not match the shapes list.
Adds blendshape inputs to a shape’s geometry.
addInBetweenShapes(primary_shape_geo, shapes, weights)
Adds in-between shapes to a blendshape input.
This sets up the required detail attributes (blendshape_shapenames and blendshape_inbetweenweights) on the primary shape’s geometry.
For an existing agent shape, in-between shapes can also be added using hou.AgentShape.addInBetweenShapes.
shapes
A hou.AgentShape sequence to add as in-between shapes. hou.AgentShapeLibrary.addShape should be called separately to add these shapes to the shape library.
weights
A float sequence specifying the weight that each in-between shape is applied at.
Raises hou.InvalidSize if the length does not match the shapes list.
Adds in-between shapes to a blendshape input.
applyUsdProcedural(stage, selection_rule, camera_path, resolution, lod_threshold, frame, optimize_identical_poses, bake_all_agents, prototype_material, instance_material, default_material)
Applies the 
crowd procedural to a USD stage.
Raises hou.OperationFailed if an error occurred when applying the procedural.
stage
The USD stage to modify.
selection_rule
A hou.LopSelectionRule specifying the SkelRoot instances the procedural should be applied to.
camera_path
A path to a Camera primitive in the stage to use for evaluating LOD.
resolution
A pair of integers specifying the output image’s resolution.
lod_threshold
The threshold at which the LOD optimization will be used. The default value of 1.0 means that the optimization will be used when tolerance between the agent poses is less than approximately 1 pixel. Lower values can eliminate deformed geometry differences which might still be noticeable depending on the scene, but make it less likely for the LOD optimization to trigger and may increase the render’s memory footprint.
offscreen_quality
Scales the approximate size of the agent in screen space for agents that are not directly visible to the camera. Smaller values will make offscreen agents more likely to become an instance of another agent.
optimize_identical_poses
A boolean value indicating whether to instance the deformed geometry for agents with exactly the same pose (including foreground agents). In most scenarios it is rare for agents to have identical poses (due to randomizing clip speeds, time offsets, etc) so this can typically be disabled to eliminate unnecessary computation.
bake_all_agents
A boolean value indicating whether to generate deformed geometry for the remaining SkelRoot Primitives which did not become an instance or prototype. This can be useful if the deformed geometry is required for subsequent procedurals. Otherwise, the deformed point positions for these agents will be generated through Hydra at render time.
frame
The time sample to apply the procedural at.
prototype_material
The path to a material to apply to SkelRoot primitives whose deformed geometry became a prototype for background instances.
instance_material
The path to a material to apply to SkelRoot primitives which became an instance of another SkelRoot’s deformed geometry.
default_material
The path to a material to apply to SkelRoot primitives which were not modified by the crowd procedural.
Applies the crowd procedural to a USD stage.
computeLocalTransforms(rig, xforms)
→ tuple
of hou.Matrix4
Converts transforms from world space to local space using the provided rig.
rig
A hou.AgentRig, which specifies the transform hierarchy.
xforms
A sequence of hou.Matrix4, with a world space transform for each joint in the rig. Raises hou.InvalidSize if the length does not match hou.AgentRig.transformCount.
Converts transforms from world space to local space using the provided rig.
computeWorldTransforms(rig, xforms)
→ tuple
of hou.Matrix4
Converts transforms from local space to world space using the provided rig.
rig
A hou.AgentRig, which specifies the transform hierarchy.
xforms
A sequence of hou.Matrix4, with a local space transform for each joint in the rig. Raises hou.InvalidSize if the length does not match hou.AgentRig.transformCount.
Converts transforms from local space to world space using the provided rig.
computeRotationLimits(rig, clips, transform, parent_transform)
→ dict
of str
to values
Computes rotation limits for the specified joint based on the range of motion in the provided clips.
The return value is a dictionary with the following keys:
-
anchor_pos: A hou.Vector3 containing the cone’s anchor position. -
rotation: A hou.Vector3 containing the cone’s orientation. -
child_rotation: A hou.Vector3 containing the child’s orientation. -
twist_limits: A hou.Vector2 containing the rotation limits for the twist axis. -
up_limits: A hou.Vector2 containing the rotation limits for the up axis. -
out_limits: A hou.Vector2 containing the rotation limits for the out axis.
rig
A hou.AgentRig.
clips
A list of hou.AgentClip.
transform
Index of a transform in the agent’s rig.
parent_transform
Index of the parent transform in the agent’s rig.
Computes rotation limits for the specified joint based on the range of motion in the provided clips.
findAgentDefinitions(geometry, group = "", group_type=hou.geometryType.Primitives)
→ tuple
of hou.AgentDefinition
Returns a list of the unique agent definitions in the geometry.
This is equivalent to the following code, but is significantly faster.
definitions = set() for prim in geometry.globPrims(group): if prim.type() == hou.primType.Agent: definitions.add(prim.definition()) return definitions
geometry
A hou.Geometry.
group
An optional group string to filter which primitives are inspected. The pattern format is the same as the format used for group parameters on SOP nodes.
group_type
A hou.geometryType indicating whether to parse the group string as a point or primitive group.
If the value is None, the group will be guessed by parsing it as a point group if it fails to parse as a primitive group.
Returns a list of the unique agent definitions in the geometry.
findShapeDeformer(name)
→ hou.AgentShapeDeformer
Finds the shape deformer with the specified name, or None if no such deformer exists.
Finds the shape deformer with the specified name, or None if no such deformer exists.
replaceAgentDefinitions(geometry, new_definition_map, group = "", group_type=hou.geometryType.Primitives)
Replaces agent definitions in the geometry with new versions. This is a useful convenience function when modifying each agent definition in the geometry, particularly when also using hou.crowds.findAgentDefinitions.
For example:
defns = hou.crowds.findAgentDefinitions(geo, group) new_defn_map = {} for defn in defns: new_defn = defn.freeze() new_defn_map[defn] = new_defn # Add a clip to the new agent definition. new_defn.addClip(...) # Switch all agents in the group to their respective new agent definition. hou.crowds.replaceAgentDefinitions(geo, new_defn_map, group)
geometry
A modifiable hou.Geometry.
new_definition_map
A dictionary mapping each hou.AgentDefinition to a hou.AgentDefinition that it should be replaced by.
group
An optional group string to filter which primitives are modified. The pattern format is the same as the format used for group parameters on SOP nodes.
group_type
A hou.geometryType indicating whether to parse the group string as a point or primitive group.
If the value is None, the group will be guessed by parsing it as a point group if it fails to parse as a primitive group.
Replaces agent definitions in the geometry with new versions.
setBlendshapeDeformerParms(base_shape_geo, attribs="P N", point_id_attrib="id", prim_id_attrib="id")
Adds attributes to the geometry to specify parameters for the blendshapes deformer.
This creates the following detail attributes: blendshape_attribs, blendshape_ptidattr, and blendshape_primidattr.
For an existing agent shape, the deformer parameters can be set using hou.AgentShape.setBlendshapeDeformerParms.
attribs
Specifies a list or pattern of attributes to be blended by the deformer.
point_id_attrib
Specifies the name of a point attribute used to match up points between the different blendshape inputs.
prim_id_attrib
Specifies the name of a primitive attribute used to match up points between the different blendshape inputs.
Adds attributes to the geometry to specify parameters for the blendshapes deformer.
shapeDeformers()
→ tuple
of hou.AgentShapeDeformer
Returns a list of the available shape deformers.
Returns a list of the available shape deformers.