Capture Regions - Houdini online help

Capture weights

In Houdini, once you associate skin geometry with bones, each point on the skin surface(s) has a point attribute which stores the degree to which the surface is influenced by different bones at that point. Where skin covers a joint, the skin can be affected by both bones according to percentages.

To initially associate the skin surface with the character, use the Capture Geometry tool.
You can edit the volume around each bone that automatically captures geometry with the Edit Capture Region tool.
You can paint the influence of bones onto surfaces with the Paint capture weights tool.
You can view the capture weight attributes on the surface numerically with the details view.

Important tools and nodes

Tools	Bones tool, Capture geometry tool, Edit capture regions tool, Edit capture weights tool, Mirror tool, Mirror capture weights tool, Paint capture weights tool
Objects	Bone object
Other nodes	Inverse Kin CHOP

Posing the character for capture

Houdini uses a character’s capture pose when it binds geometry by proximity to the bones. The capture pose does not have to be the same as the character rigging rest pose. You can pose the character specifically for capturing geometry, based on the position of the skin model.

Choose Edit > Objects > Bone Kinematics Override: Capture Pose.
Pose the character to match the model geometry.
To return to normal posing, choose Edit > Objects > Bone Kinematics Override: None.

Tip

This submenu also lets you edit the “rest” pose that controls IK the solution. See how to edit the rest position.

Paint capture weights

See Paint Capture Layer shelf help.

Detail Attributes

If you are using the Auto Rig you will not have to deal with detail attributes. However, if you are building your own character the following capture attributes are stored in detail attributes.

pCapt	Output by the Capture and Capture Proximity SOPs, stores the point weighting information. It consists of pairs of the capture region index in the pCaptPath attribute along with its associated weight.
pCaptAlpha	Output by the Capture Layer Paint SOP, contains the painted alpha information.
pCaptPath	Output by the Capture and Capture Proximity SOPs, a list of entries indicating the regions used in the capture process. Each entry consists of a path to the SOP relative to pCaptSkelRoot (below) followed by the corresponding primitive number in the SOP.
pCaptData	Output by the Capture and Capture Proximity SOPs, contains the rest transforms of the capture regions at the time of capturing.
pCaptFrame	Output by the Capture and Capture Proximity SOPs, contains the rest frame at which the data was captured.
pCaptSkelRoot	Output by the Capture and Capture Proximity SOPs, contains the parent path of all entries in the pCaptPath attribute.