Houdini 20.0 Nodes Geometry nodes

HeightField Mask by Occlusion geometry node

Creates a mask where the input terrain is hollow/depressed, for example riverbeds and valleys.

Since 17.0

The node calculates measures occlusion as “how much of a sphere centered on the point is visible from the given point.” It sends rays from each point in different directions and measures how many hit terrain before reaching their maximum distance.

Parameters

Masking

Combine with Existing

How to combine this mask with any existing mask in the input.

Replace

Clear the existing mask and replace it with the new mask.

Add

Add the values in this mask to any existing mask.

Subtract

Subtract the values in this mask from any existing mask.

Difference

Set the mask values to the difference between the old mask and this mask.

Multiply

Multiply the values of the old mask by the values in this mask. This might be useful to “scale” existing values while leaving empty areas alone.

Maximum

Set the mask values to the maximum of the old mask and this mask.

Minimum

Set the mask values to the minimum of the old mask and this mask.

Blend

Blend the old mask and this mask by a certain amount.

Blend

The amount to blend the old mask with what you draw, when Combine with existing is “blend”. A value of 0 leaves the existing mask, a value of 1 replaces with the new mask, a value of 0.5 blends equally between the old and new mask.

Minimum Occlusion

Scales the output mask. Areas with occlusion less than or equal to this value will have mask 0.0.

Maximum Occlusion

Scales the output mask. Areas with occlusion greater than or equal to this value with have mask 1.0.

Occlusion Ramp

A ramp mapping the sunlight exposure at a given point (ranging from 0 to 1, with higher values being more exposed) to the mask value at that point.

Sample from Hemisphere

Instead of measuring the visibility of a sphere centered on each point, measure the visibility of a hemisphere in the Y direction.

Quality

View Distance

How far to send rays to determine if a point can see the sky. Longer distances give more accurate measurements, but can be slower. A value of 0 corresponds to a view distance of infinity.

Step Scale

How finely to step along the rays to determine if a point can see the sky. Larger values are faster but might miss thin features.

Number of Searches

How many rays to send to determine if a point can see the sky. Larger numbers give more accurate measurements, but can be slower.

Layer Bindings

Mask Layer

If a mask volume is wired into this node’s second input, this specifies which volume in the second input to use to mask this node’s effect, usually mask. Click the “Add mask paint” button to paint the mask directly in the viewport (this automatically adds a paint node to the second input).

Height Layer

The name of the height volume to operate on, usually height.

Geometry nodes