Advanced RayTrace



Table of contents:

Description:
This node is an extended version of LightWave's own RayTrace node, giving you more control about settings of the raytrace operation.

Location:
The node will be added to the "Pom's Nodes/Surfacing" menu under the name "Advanced RayTrace".
Settings:

Position:
The x, y and z world-coordinates from which the ray will be cast.

Direction:
The normalized direction in which the ray will be cast. Usually the surface normal.

Mode:
Here are some quotations directly from the SDK documentation

Distance: Only returns the distance to the closest surface. This mode does not recurse. It can hit fully transparent surfaces. The ray's position, direction and flags are used. Only distance is returned.

Reflection: This casts a reflection ray and shades the surface that is hit. It uses ray recursion. All parameters except eta (refraction index) are used. Distance and color are returned.

Refraction: This casts a refraction ray and shades the surface that is hit. It uses ray recursion. All parameters are used. Distance and color are returned.

Dissolve: This casts a dissolve ray and shades the surface that is hit. It uses ray recursion. Dissolve is a special case of a refraction ray. It will never hit the object that cast the ray. All parameters are used. Distance and color are returned.

Shadow: This calculates the shadow occlusion along a ray. The ray does not recurse or bend at each intersection. At each surface intersection, the opacity is calculated and combined with the ray's current opacity. The order in which the surfaces are intersected is unpredictable. The ray's position, direction and flags are used. Color and distance are returned.

Occlusion: This casts an occlusion ray. The ray does not recurse or bend at each intersection. Occlusion is a special case of a shadow ray. The difference is in the way it uses the object's normal ray visibility flags instead of the object's shadow visiblity flags. The ray's position, direction and flags are used. Color and distance are returned.

Backdrop: This casts a backdrop ray. The ray only intersects the backdrop color. It does not recurse.

Refraction Index:
This is the refraction index that will internally passed on to other nodes.

Color:
The color used as an initial input for the raytrace operation (see below).

Flags:
A few more quotations directly from the SDK documentation

Backshade: Causes shaders to be called when the back side of a surface is hit by a ray.

Backdrop: Makes the raytrace functions use the color parameter as the backdrop color instead of calculating it prior to casting the ray. This allows a plug-in to override the backdrop color.

Object: Restricts the rays to only intersecting the same object that cast the ray. This is useful for shaders that calculate sub-surface scattering.

Sampled Ray: Should be set by the plug-in when it is using multiple rays to calculate illumination. An example would be for soft relfections. This allows shaders to restrict the number of rays that they cast to calculate illumination. This can greatly speed up renderings without degrading the image quality.

No Polygon: Allows the rays to hit the same polygon that cast them. This is useful for shaders that cast frays from a point in front of a surface.



Settings

Advanced Settings