Alpha layer of a terrain can be used to cutout a non-rectangular
shape for display. The cutout occurs at a
0.5, but some care should
be taken to ensure the value varies smoothly to avoid a wavy cutout.
This node converts the geometry into a matching resolution VDB, if
it is not already a VDB, and then sets the
Alpha layer to be displayed
if it is inside the object.
Alpha to one outside of the object rather than inside.
How to merge with any existing
Alpha. If no layer exists,
a layer of value
1 will be created.
Ignore previous values.
Minimum of the two values, so only present where both are present.
Maximum of the two values, so present where either are present.
Minimum of the old value an complement of the new value - this will bite out the new object from the previous cutout.
Crop to Bounds
Alpha layer is purely a visual effect - the terrain
will continue to exist over all the clipped values. When cropping
is enabled, the terrain will be shrunk to the smallest rectangular
region that is active.
Which layer to apply the cut out changes. The standard visualizers
Alpha for clipping.
Which layer to use for height computation. To find if a voxel is inside the object, it has be lifted from the ground plane by the height value.