Houdini 20.0 Nodes VOP nodes

Run External Program Procedural VOP node

This procedural will run an external application in order to generate geometry at render time.

Since 11.0

The name of the program to run must be specified. Alternatively, a second program string can be specified to generate motion blurred geometry.

Before the program is run, the program string is scanned for the sub-string %LOD. All occurrences of this sub-string are replaced with the level of detail computed by mantra (a floating point number representing the screen space).


This procedural requires a bounding box to be specified. When generating motion blurred geometry, the bounds must enclose the blurred geometry as well.




The program to run to generate geometry. For example, myprogram.pl arg1 arg2 %LOD.

Blur Program

The program to run in order to generate geometry at the end of the frame. If no program is specified only transformation motion blur will occur.


The shutter time when rendering motion blur.

IFD Bounds

Bounding Box

The bounding box controls let you specify a bounding box for the referenced geometry. Only when this bounding box is “on screen” will mantra load the referenced geometry. You can set Bounding Box to No bounding box required, in which case mantra will always load the references geometry regardless. You can also specify the bounding box by referencing the SOP’s bounding box in the SOP Bounds parameter.

SOP Bounds

The geometry whose bounding box you want to reference.

Min Bounds

The minimum bounding box dimensions, when setting explicit bounds.

Max Bounds

The maximum bounding box dimensions, when setting explicit bounds.

VOP nodes