Houdini 21.0 Nodes Copernicus nodes

Ray Trace Copernicus node

Performs ray tracing on an input mesh based on an origins and directions map.

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Since 21.0

This node intersects rays against the incoming geometry, outputting information about the first intersection. In addition to the location of the intersection and the geometric normal at that point, this node can compute several built-in maps (such as occlusion and curvature) by tracing secondary rays. This node can also read a geometry’s attribute values at the ray intersection and write them to an output layer.

The rays to shoot are read from the origins and directions input layers. Every pixel from origins that has a non-zero value in directions casts a corresponding ray. Optionally, you can tag the rays with a trace set to isolate parts of interest for each ray. The tracesets ID layer contains the value each ray must use, and a ray only sees parts of the geometry that have this same ID value in the Trace Set Attribute. This allows you to cast rays that only intersect against specific (but varying) subsets of the input geometry.

Parameters

Tracer

The tracer to use. This is an automatic menu that shows only available options based on your hardware.

Note

Optix is available on only NVidia hardware.

Ray Bias

The amount to offset a ray’s origin from the origins map along the directions.

You can use this parameter to arbitrarily offset the tracing mesh along its normal.

Cull Backface Mode

The method used to handle secondary rays that interact with the geometry.

No Culling

Don’t ignore any secondary rays.

Back-faces

Ignore any secondary rays that hit the back-faces of the geometry.

Front-faces

Ignore any secondary rays that hit the front-faces of the geometry.

Trace Direction

The direction that the rays travel relative to its origin and direction.

Bidirectional

Two way, fire rays both forward and backward.

Forward

Fire rays the same direction as directions.

Reverse

Fire rays the inverse of the directions.

Trace Set Attribute

The attribute on the geometry to look for to match trace sets with the tracesets input. If one part of a mesh on the tracesets ID layer is 1 and the Trace Set Attribute on the geometry has a section with a value of 1, these two pieces are traced only to each other and ignore all other geometry.

Occlusion

Occlusion

Bakes the Occlusion map, which bakes the effect of indirect lighting and shadows from the geometry. When off, the occlusion output is a Null layer.

Use ambient occlusion to fake shadows, particularly in areas where objects are close together.

Occlusion Samples

The number of indirect rays to use when computing Occlusion. Increase this value if the resulting AOV is noisy.

Max Distance

The maximum distance to consider when computing Occlusion. A small distance can speed up occlusion shading at the cost of accuracy.

Cavity

Cavity

Bakes the Cavity map, which computes the concave details of the geometry. When off, the cavity output is a Null layer.

Use this for masking indents or cracks in the geometry.

Cavity Samples

The number of indirect rays to use when computing Cavity. Increase this value if the resulting AOV is noisy.

Max Distance

The maximum distance to consider when computing Cavity. A small distance can speed up cavity shading at the cost of accuracy.

Bias

The ray bias when computing Cavity.

Curvature

Curvature

Bakes the Curvature map, which bakes concavity and convexity. Concave details are brighter while convex details are darker. When off, the curvature output is a Null layer.

Curvature Samples

The number of indirect rays to use when computing Curvature. Increase this value if the resulting AOV is noisy.

Curvature Scale

The overall curvature strength.

Max Distance

The maximum distance to consider when computing Curvature. A small distance can speed up curvature shading at the cost of accuracy.

Bias

The amount to shift the contrast to emphasize convexity (0.0) or concavity (1.0).

Thickness

Thickness

Bakes the Thickness map, which generates a map based on the thickness of the geometry. Thicker areas create darker values and thinner areas create brighter values. When off, the thickness output is a Null layer.

Thickness Samples

The number of indirect rays to use when computing Thickness. Increase this value if the resulting AOV is noisy.

Edge

Edge

Bakes the Edge map, which creates a map of the edges on the mesh. When off, the edge output is a Null layer.

Use this to fake beveled edges on hard surfaces.

Edge Samples

The number of indirect rays to use when computing Edge. Increase this value if the resulting AOV is noisy.

Mode

The types of edges (concave or convex) to smooth.

Radius

The radius when computing Edge.

Cusp Angle

The cusp angle when computing Edge.

Rounded Normal

Rounded Normal

Bakes the Rounded Normal map, which creates a normal map from the edges on the mesh. When off, the roundednormal output is a Null layer.

Use this to fake beveled edges on hard surfaces.

Rounded Normal Samples

The number of indirect rays to use when computing Rounded Normal. Increase this value if the resulting AOV is noisy.

Mode

The types of edges (concave or convex) to smooth.

Radius

The radius when computing Rounded Normal.

Cusp Angle

The cusp angle when computing Rounded Normal.

Custom Attributes

Custom Attributes

The number of custom attributes to rasterize.

Attribute Name

The name of the attribute to rasterize. This must match the attribute present on the geometry input. This can be Point, Vertex, or Primitive.

Type

The output type for the rasterized attribute. To be rasterized, an attribute must be either an integer or a float of four or less components.

See Data types for more information.

Inputs

geometry

The geometry to ray trace against.

origins

The RGB map of the positions from which to fire rays.

directions

The RGB map of the orientations along which to fire rays.

tracesets

The ID layer of the sets to evaluate on each hit of the geometry.

Outputs

intersections

The intersection data of the rays fired against the geometry.

normals

The geometric normal of the intersection point of the rays fired against the geometry.

occlusion

The map of the effect of indirect lighting and shadows from the geometry.

cavity

The map of the concave details of the geometry.

curvature

The map of the concavity and convexity of the geometry. Concave details are brighter while convex details are darker.

thickness

The map based on the thickness of the geometry. Thicker areas create darker values and thinner areas create brighter values.

edge

The map of the edge details of the geometry.

roundednormal

The map of the rounded edge normal of the geometry.

output#

The rasterized custom attribute. The amount of attribute outputs and their details are based on the Custom Attributes information.

See also

Copernicus nodes