Houdini 20.0 Nodes Geometry nodes

Transform geometry node

The Transform operation transforms the source geometry in “object space” using a transformation matrix.

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The Transform operation transforms the source geometry in “object space” using a transformation matrix.

All primitives selected will receive the same transform. To vary the transform by a point attribute, use the Transform By Attribute SOP.

Note

Vector VDBs will have their internal values transformed according to the transform hint in their intrinsic data.

SDF VDBs will not have their internal values updated, even if a uniform scale is performed. This can be done with a VDB Combine by setting the A Multiply value to the scale amount.

In Houdini’s row vector convention, if P is the matrix representing the pivot translate and rotate, M is the matrix representing the translate, rotate, scale and shear parameters, and N is the matrix representing the pre-transform translate, rotate, scale and shear parameters, then the net transform is inverse(P)*M*P*N.

Parameters

Group

Subset of geometry to transform.

Group Type

The type of elements referenced in the Group field.

Transform Order

Order in which transformations occur.

Rotate Order

Order in which rotations occur.

Translate

Amount of translation along xyz axes.

Rotate

Amount of rotation about xyz axes.

Scale

Non-uniform scaling along xyz axes.

Shear

Amount of shearing. The three values represent shearing in the X direction on the XY plane, in the X direction on the XZ plane, and in the Y direction on the YZ plane, respectively.

Uniform Scale

Uniform scaling.

Pivot Transform

Pivot Translate

The local pivot space’s translation value for transformations.

Pivot Rotation

The local pivot space’s rotation value for transformations.

Pre-Transform

Pre-Transform Order

Order in which transformations occur inn the pre-transform.

Ptr-Rotate Order

Order in which rotations occur in the pre-transform.

Pre-Translate

Amount of translation along xyz axes in the pre-transform.

Pre-Rotate

Amount of rotation about xyz axes in the pre-transform.

Pre-Scale

Non-uniform scaling along xyz axes in the pre-transform.

Pre-Shear

Amount of shearing in the pre-transform. The three values represent shearing in the X direction on the XY plane, in the X direction on the XZ plane, and in the Y direction on the YZ plane, respectively.

Attributes

These attributes are transformed, if they are marked as transforming. Use Attribute Create to set the transformation type on an attribute to Position, Vector, Normal, Quaternion, or Transform Matrix. Set the type to None to make an attribute non-transforming, or remove it from this list. Primitive transforms are affected if and only if P is transformed.

Recompute Point Normals

Recomputes all normals as point normals, if a normal attribute exists.

Recompute Affected Normals

Recomputes any normals that are affected by polygons that use both transformed and untransformed points. When transforming the full geometry or full connected components, the results should be the same as when this option is off, i.e. the normals will just be transformed and not recomputed. This does nothing if P is not being transformed.

Preserve Normal Length

Normal lengths remain unaffected.

Invert Transformation

Use the inverse of the transformation. This is the transformation which undoes the specified transformation. Two transform SOPs with all parameters but this equal will cancel out each other’s transformation.

Output Attribute

If this field is not blank, the node creates a detail attribute with this name, containing a 4×4 matrix representing the applied transform. You can use this, for example, to apply the same transform elsewhere, or reverse the transformation later in the chain.

Combine

If the Output attribute already exists, this controls how/whether the node combines the new transform with the existing one in the attribute. “Post-multiplication” applies the transform in the same way as if you wired multiple transform nodes to each other in the network.

Locals

CEX, CEY, CEZ

The centroid of the input

GCX, GCY, GCZ

The centroid of the input group

XMIN, XMAX

The X extents of the bounding box of the input

YMIN, YMAX

The Y extents of the bounding box of the input

ZMIN, ZMAX

The Z extents of the bounding box of the input

SIZEX, SIZEY, SIZEZ

The size of the bounding box of the input

Examples

ModulusTransform Example for Transform geometry node

Create a cyclical animation using the Transform SOP, the Group SOP, and the modulus operation.

See also

Geometry nodes