Houdini 20.0 Nodes Geometry nodes

Capture Region geometry node

Supports Capture and Deform operation by creating a volume within which points are captured to a bone.

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Typically one or more Capture Regions are placed in an object (usually a bone) and named “capture_region”. The object is then read into a Capture operation through the object’s hierarchy. The object is moved to deform the Capture operation’s geometry with a Deform operation.

The Capture Region volume is a tube with hemispheres at each end. By adjusting the shape of the capture region, you can affect how points are weighted by the Capture operation. The closer a point is to the edge of a region, the lighter the weight. Thus you can increase point weighting by increasing the size of the region.

The parameters in the Region tab define the values used for deforming the skin points while the values in the capture tab define the values used for capturing them. The shape of the capture region used for capturing can be viewed by setting Edit ▸ Objects ▸ Bone Kinematic Override: Capture Pose from the main menu.

Rig Adjustment parameters define a transform that nullifies deformations that may be caused by bone position tweaking during a rigging process. This happens after the geometry has been captured when bone joints need to be adjusted to improve animation. After capturing, moving a bone is going to deform the captured geometry. To reset this deformation, the capture region in a deforming (animating) pose needs to be aligned back with the capture region in a capturing pose. A transformation defined by the Rig Adjustment parameters aligns the deform and the capture incarnations of the capture region. This transformation is automatically calculated by the Align Capture Pose tool or when an hscript command “bonealigncapture” is invoked on bones. On a side note, the transform order of the rig adjustment is RTS and rotation order is ZYX.

Using Edit Capture Region

  1. Select the bones to edit.

  2. Click the Edit Capture Regions tool on the Characters tab.

  3. Drag the arrows to edit the bone capture regions.

Note

You can change the Edit Region in the operations toolbar to Deform Geometry if you want to edit the capture geometry.

Parameters

Region

Animate

Orientation

Defines the direction axis of the region. Use Z axis when the region is inside a bone object.

Center

Position of the center of the region /t[xyz].

Rotate

Orientation of the region expressed as rotational angles in degrees around x, y, and z axis. The order of rotation follows that of a bone and is ZYX. Rotation is performed around the center of the region. /t[xyz].

Squash and Stretch

Scaling parameters in the x, y, z axis direction of a local reference frame. Effectively, the parameters Center, Rotate, and Squash and Stretch for a transformation matrix with the RTS transform order and ZYX rotation order /squash[xyz].

Top Height

Height of the region from the center to /theight the top cap.

Top Cap

X,Y,Z radii of the top hemisphere /tcap[xyz].

Bottom Height

Height of the region from the center to /bheight the bottom cap.

Bottom Cap

X,Y,Z radii of the bottom hemisphere /bcap[xyz].

Height Scale

Scaling factor for both Top and Bottom Height parameters /hscale.

Rig Adjustment

Rig Adjust Translate

translation /rigadjustt[xyz].

Rig Adjust Rotate

rotation /rigadjustr[xyz].

Rig Adjust Scale

scale /rigadjusts[xyz].

Rig Adjust Z Factor

coefficient that scales the animation z-factor to equal the capture z-factor /rigadjustzfactor.

Capture

Orientation

A capture counterpart of the Orientation parameter in Region tab.

Center

A capture counterpart of the Center parameter in Region tab.

Rotate

A capture counterpart of the Rotate parameter in Region tab.

Squash and Stretch

A capture counterpart of the Squash and stretch parameter in Region tab.

Top Height

A capture counterpart of the Top Height parameter in Region tab.

Top Cap

A capture counterpart of the Top Cap parameter in Region tab.

Bottom Height

A capture counterpart of the Bottom Height parameter in Region tab.

Bottom Cap

A capture counterpart of the Bottom Cap parameter in Region tab.

Height Scale

A capture counterpart of the Height Scale parameter in Region tab.

Inner/Outer Weight

Defines the weight of a point exactly on the center line and edge of the region respectively. Point weights in between will be blended.

Display

Display Color

The Capture operation uses region colors for helpful feedback. By default the region inherits the color of its containing object (via an expression).

See also

Geometry nodes