Field opacityThreshold

The opacityThreshold input is useful for creating geometric cut-outs based on the opacity input.

Namespace: USD.NET.Unity

Assembly: solution.dll

Syntax

[InputParameterAttribute]
public Connectable<float> opacityThreshold

Returns

Type	Description
Connectable<float>

Remarks

A value of 0.0 indicates that no masking is applied to the opacity input, while a value greater than 0.0 indicates that rendering of the surface is limited to the areas where the opacity is greater than that value. A classic use of opacityThreshold is to create a leaf from an opacity input texture, in that case the threshold determines the parts of the opacity texture that will be fully transparent and not receive lighting. Note that when opacityThreshold is greater than zero, then opacity modulates the presence of the surface, rather than its transparency - pathtracers might implement this as allowing ((1 - opacity) * 100) % of the rays that do intersect the object to instead pass through it unhindered, and rasterizers may interpret opacity as pixel coverage. Thus, opacityThreshold serves as a switch for how the opacity input is interpreted; this "translucent or masked" behavior is common in engines and renderers, and makes the UsdPreviewSurface easier to interchange. It does imply, however, that it is not possible to faithfully recreate a glassy/translucent material that also provides an opacity-based mask... so no single-polygon glass leaves.