Houdini 19.0 Nodes Geometry nodes DeltaMush

DeltaMush geometry node

Smooths out (or “relaxes”) point deformations.

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Since 15.5

This node is used smooth out the effect of point deformations by a copy of the geometry before it was deformed.

To smooth out bone deform geometry, append this node to the output of a Bone Deform SOP and use the input of the Bone Deform SOP as the second input.

For example,

In general, the deformation can be from any source (eg. from simulation).


This node assumes non-manifold polygonal geometry (ie. there are no edges that have more than two adjacent polygons).



Subset of points to smooth.


The weighting method used for smoothing.


Fastest method but assumes that the edge lengths are roughly the same everywhere.

Edge Length

Uses the edge length to weight the smoothing so that more details are maintained. It can also prevent points from seemingly drift along the surface.


The number of smoothing iterations to apply. More iterations result in smoother results. Generally, more iterations are needed for the same amount of smoothing for geometry that has higher point counts at the same size.

Step Size

The amount of smoothing applied for each iteration. Larger step sizes result in smoother results. If there are artifacts in the results, try using smaller step sizes along with more iterations (at the expense of longer cook times).

Pin Border Points

By default, delta mush will smooth everything. Turning this on will prevent the smoothing of border points that lie along unshared edges. For curves, only the end points are considered as border points.

Recompute Affected Normals

Recomputes any point (or vertex) normals that are affected by the smoothing operation. This option has no effect if the input geometry does not have a normal attribute.

Clamp Step Size

When enabled, the step size value will be limited to be between 0 and 1 since the algorithm works best in this range.


DeltaMushDemo Example for DeltaMush geometry node

This example demonstrates how the Delta Mush SOP is used to smooth out bone deformation.

See also