Houdini 13.0 Nodes

interface version 1

Discard geometry outside of a bounding box (or a convex shape).

This is a convenience operator, providing various ways of deleting geometry outside of a specified bounding box.

The following methods are available:

  1. Delete: simple deletion of points or primitives that fall outside the bounding box. Fast, but can be inaccurate (as it works on entire primitives).

    This option can be used in itself, or as a quick pre-processing for method #2 or #3 (so the accurate clip operations would work on less geometry).

  2. Clip (by Bounding Box): Performs a clipping operation for each side of the bounding box. Provides accurate results, but can be slow for heavy geometry.

  3. Clip (by Individual Polygons): Performs a series of clipping operations, where each polygon from the second input will be used as a clipping plane.

    Each polygon’s centroid and face normal will determine the cutting plane placement. This polymesh should have as few faces as possible with properly oriented face normals.

    Although there are no restrictions on shape, in practice only convex shapes work properly. A practical example is to clip with a frustrum created by a Camera Frustrum qL SOP.

Inputs

The first input is the geometry to clip, the second is a bounding box or a polygonal mesh (usually generated by a Bounds qL SOP, a Bound SOP, or a Camera Frustrum qL SOP operator.)

Parameters

Delete Outside

If enabled, the specified geometry components outside the bounding box will be deleted first (before doing any clipping).

Offset

An extra offset for the boundary of the outside-component deletion.

Delete Inside

This deletes geometry inside the bounding box instead of outside.

Clip Using

Perform an accurate (per-primitive) clipping of the input geometry, for the specified bounding box.

Off

No geometry clipping is performed.

Bounding Box

Geometry will be clipped using the bounding box of the second input geometry.

Individual Polygons

Geometry will be clipped using the polygons of the second input geometry: a clipping is performed for each polygon, using its centroid and face normal to determine the clipping center and direction.

Lower, Upper Padding

Additional offsets for the input bounding box.

X/Y/Z -/+

(Only in Bounding Box mode) With these six toggles each main clipping plane can be enabled or disabled.

Release Notes

interface version 1 —

2014-05-16

  • 2nd input “reference”

  • Added “Flip Polygon(s)” for per-poly clipping

2013-09-21

  • Added “Delete Inside” toggle.

2013-08-27

  • Supports self-clipping: if no second input is given, the geometry’s own bounding box is used as clip bounds.

  • Added “Individual Polygons” clip mode (each polygon is used as a clipping plane).

2013-06-28

First version.