Houdini 13.0 Nodes

Version 0.0.2

Converts between different representations of per-point orientation (rotation).

In Houdini there is more than one way to represent orientation (i.e. rotation) on a per-point basis. This node allows to easily convert between these representations. The following methods are supported:

Aim / up vector pairs

Rotation on each point is represented by two vectors. The aim vector is usually N (normal) or v (velocity). The up vector should always be named up.

Orient (quaternion) attribute

A single per-point quaternion (vector4) attribute called orient stores the rotation for each point. This is more efficient but not 'human-friendly'.

Both ways are supported throughout Houdini wherever per-point orientation is needed (e.g. particle instancing, Copy SOP, etc).

If vectors and quaternions are both present, quaternions take preference.

Parameters

Operation

Main operation settings.

Operation

Main operation mode.

Construct

Build orient attribute from vector pairs.

Extract

Extract vector pairs from the orient attribute.

Aim Vector

Name of the vector attribute that represents the aim direction for each point. It is usually N (normal) or v (velocity).

Up Vector

Name of the per-point up vector attribute (by default it’s called up).

Orient Attribute

Attribute representing per-point orientation (in a quaternion form). The Houdini-supported attribute name is orient (type vector4).

Delete Source Attribute(s)

When converting to orient this will delete the vector pairs, and vice versa.

Extract

These parameters are used when quaternion orientations are extracted back to aim/up vector pairs.

Initial Aim

The resulting aim vector will be this vector with the quaternion rotation applied.

Initial Up

The resulting up vector will be this vector with the quaternion rotation applied.

Release Notes

Version 0.0.2

  • Support for arbitrary base aim/up vectors on extract

  • Known limitation of 0.0.1 is lifted (H12+)

  • Some UI cosmetics.

Warning

Non backwards-compatible parameter changes:

  • Parameter 'attr_N' renamed to 'attr_aim'

Version 0.0.1

Initial release.

KNOWN LIMITATION

When converting from Orient to Aim/Up, the resulting Aim vector will always be written as a per-point N (normal), too.