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A crowd object’s clip transition graph may optionally be used to control transitions between states and animation clips. It provides information about which clips are allowed to transition to each other, and where in the clips those transitions should occur. This can be used by the Crowd Transition DOP to delay state transitions until an appropriate point in the current animation clip, and to smoothly blend into the next clip. Additionally, the clip transition graph allows per-clip control over this behavior (which is useful if the transition’s Input State parameter specifies multiple states, or if Randomize Clips is enabled for any of the input states).
The Test Simulation: Crowd Transition SOP can be used to quickly preview transitions between particular clips before setting up a crowd simulation.
Each point in the clip transition graph geometry represents an animation clip, and each two-point polygon represents a (one-way) transition between the clips. During a state transition, if the points corresponding to the input and output states' animation clips are not directly connected, the Crowd Transition DOP will use the shortest path between the two clips.
Specifies the name of an animation clip.
This string is matched with the agent’s
For each transition region, specifies the duration (in seconds) of any transitions which start in that region.
For each transition region, specifies a pair of clip times (in seconds) where the two animation clips have a similar pose.
Specifies ranges of clip times (in seconds) for the first animation clip where a transition is allowed to occur.
The units for which time parameters are specified. This can be frames (at the Houdini FPS) or samples (in the clip’s sample rate).
Compute Transition Graph
Automatically build a transition graph for the agent’s animation clips. For each pair of clips, this searches for groups of consecutive frames where the agent’s poses are similar.
Specifies a tolerance for how similar the agent’s poses must be.
Specifies the length of the transitions between animation clips.
When comparing pairs of poses, the comparison can be limited to a particular group of transforms from the agent’s rig (such as the lower body).
Restricts the pairs of clips to search for transition points between. The standard pattern matching syntax (such as that used by the match VEX function) can be used to specify multiple source and destination clips.
For example, to exclude transitions from a
sit_to_stand clip to the
sit clip, and only search for transitions to the
stand_2 clips, Clip A could be set to
sit_to_stand and Clip B could be set to
If a clip does not match at least one of the Clip A patterns, all other clips will be considered as potential destination clips (matching the behavior when no filters are specified).
Including a filter where Clip A is set to
* and Clip B is empty will exclude all transitions except for the ones specified by the other filters.
The number of additional transitions to set up between pairs of animation clips.
The name of the animation clip to transition from.
The name of the animation clip to transition to.
Initialize from Computed Transition Regions
Sets the transition region parameters to the computed values if Compute Transition Graph is enabled. This can be used to perform manual edits to the computed transition regions.
The number of regions in the clip where a transition may occur.
Sync Frame A
Specifies a frame in Clip A where the pose is similar to Sync Frame B in Clip B.
Specifies the range of frames where a transition may begin. This should typically include Sync Frame A.
Sync Frame B
Specifies a frame in Clip B where the pose is similar to Sync Frame A in Clip A.
Specifies the length of the transition between the clips.