Houdini 20.5 Nodes VOP nodes

Karma Pyro Volume Mask VOP node

Creates a volume mask used for volume shading.

On this page

Overview

This node reads in a volume, density by default, and outputs a color mask value which can be used to scale emission for volume shading. Turn off the checkbox in front of Mask Volume to use any custom values for input, which can be provided through the mask_volume input.

This node is intended as a building block for building larger volume shader.

Parameters

Masking

Mask Center

In conjunction with Mask Width, this parameter controls the range of values used for masking emission. The effective range of mask values is from Mask Center - Mask Width * 0.5 to Mask Center + Mask Width * 0.5. When set to a lower value, more of the emission will be masked and the explosion will glow less brightly. When set to a higher value, the volume will appear to glow internally, with this glow peeking through cracks in the smoke.

The video shows the effect of increasing this parameter while keeping Mask Width fixed.

Mask Width

Controls the range of values used for masking emission, in conjunction with Mask Center. The effective range of mask values is from Mask Center - Mask Width * 0.5 to Mask Center + Mask Width * 0.5.

Use Mask Ramp

Use a ramp to set how the emission changes between the minimum and maximum mask threshold (as set by Mask Center and Mask Width).

Mask Ramp

Sets how the emission changes between the minimum and maximum mask values (as set by Mask Center and Mask Width). White means full emission and black means no emission.

Note

The default white to black ramp will produce the exact same results as having Use Mask Ramp turned off.

When the ramp is set white to black from left to right:

When the ramp is set black to white from left to right:

Bindings

Mask From Geometry

When turned on, use the mask volume (given by Mask Volume) as the mask source. Otherwise, use the maskvolume input connection on the node.

Mask Volume

The name of the volume used to generate the mask volume.

See also

VOP nodes