Houdini 21.0 Nodes Geometry nodes

Edge Relax geometry node

Moves points such that edge lengths match a reference.

This node moves points around so the edges between them match those specified by the second input.

Points can optionally be constrained to the input surface or another optional surface connected to the third input.

This is intended for, but not limited to, use as a helper node for the Muscle Transfer SOP to prevent transferred muscles or bones from being bunched together because of bunched up edges in the target mesh compared to the source mesh.

Parameters

Group Type

Specify whether to operate on a point or a primitive group.

Primitives

Operate on a group of primitives.

Points

Operate on a group of points.

Group

The group to operate on.

Group from Reference Input if Wired

If the reference input is wired, evaluate the group on this input. This can speed up some operations if the second input isn’t changing (over time for example), so the group doesn’t have to be reevaluated.

Iterations

The number of relaxtion iterations.

Step Size

Controls how much points are moved each iteration. Larger step sizes have a greater effect per iteration, but may cause instability. If there are artifacts in the results, try using smaller step sizes along with more iterations (at the expense of longer cook times).

Pin Group

A group of points to pin in place.

Second Input Type

Reference Positions

Compute reference edge lengths from point positions. Topology of this input must match that of the first input.

Reference Edge Lengths (Line Network)

Use an attribute on polygon primitives connecting points as the reference length. This can be used for advanced effects that require more control over reference length.

Target Mode

Individual Edge Lengths

Each edge converges towards its individual reference length.

Scale-Independent Edge Length Distribution

Normalizes by mean edge length, removing effects from overall scale difference between inputs from the relaxation.

Rest Length Attribute

The primitive attribute to use as reference length when Second Input Type is Reference Edge Lengths (Line Network).

Only Shorten Edges

Only ever shorten edges. This will usually result in very similar results, while making the computation far more stable.

Lengthening edges can results in fairly random motion in some cases, since no angle constraint is applied by this operator.

Slide on Surface

Slide on Surface

Constraints motion of points to the surface, sliding them over the first input’s surface or the third input’s surface if that is connected.

Slide Iterations

Number of sliding iterations. A fraction of relax iterations is performed between these slide intervals.

Undistort (Slow)

Sliding can result in result in losing spikes & ridges within the surface. This option can restore these to some extent. Beware that this is can result in much longer cook times when lots of sliding iterations are used.

Anisotropic Scale

Use Anisotropic Stretch

Squash/stretch edges in a specific direction, specified by a vector attribute on points.

Local Direction Attribute

The direction attribute specifying stretch direction.

Anisotropic Scale

The scale factor applied in the local direction at each point.

No Scaling

Use the Anisotropic Scale parameter as is.

Scale by Attribute

Multiply the Anisotropic Scale parameter by the value of an attribute at each point.

Volume Preservation

Missing description.

No Scaling

Missing description.

Scale by Attribute

Missing description.

See also

Geometry nodes