Occlusion material

This is an all purpose Ambient Occlusion material with a choice of various color options.

This is a new feature in Houdini 10. To learn about more new features, see what’s new in Houdini 10.

This is an all purpose Ambient Occlusion material with a choice of various color options. Ambient Occlusion is typically multiplied as a separate pass in compositing however some also choose to use it as a simple form of cartoon shader as well. With that in mind there are options for fitting the light and dark areas of the occlusion into a color ramp, options for feeding an environment map into the occlusion and options for surface coloring outside of the occlusion construct.

Parameters

Mask for Compositing

As Ambient Occlusion is most often used as a separate pass for compositing, this toggle can be used to eliminate all of the color options and invert the color output. In this way, it is simple to create a mask that can be used in comp. When enabled, only the basic options for occlusion are available.

Occlusion

Object Scope	A list of objects in the scene which will participate in the occlusion. By default will include all categories using the wildcard symbol.
Categories	A list of categories which will participate in the occlusion. By default will include all categories using the wildcard symbol. see light linking for more information.
Number of Samples	Specifies the amount of samples that should be sent out to filter rays. Lower values will result in faster renders, but lower quality. Higher values are recommended for the final render than the default value of 64.
Maximum Ray Distance	This parameter is used to adjust the sensitivity of the occlusion. This is very reliant on your scene scale. If the maximum ray distance is set to -1, the rays will be allowed to travel to infinity.
Bias	Gives control over self-intersections. This should typically be a very small number.
Occlusion Colors	Determines which method is used to control the colors of the occlusion material. Use Color Ramp will allow use of the Color Mapping Ramp, while Use Environment Map will feed an Environment Map through the Occlusion calculations.

Color Ramp

Color Mapping

This is a ramp type parameter which will map the dark and light values from the occlusion calculation to user controlled colors. By default, the shadowed values will be black, while the ambient values will be grey. The defaults provide the same result as what the direct output from the Occlusion VOP would be.

Environment Map

Tint	This parameter is used to tint the values of the Environment Map. While the Base Color will always tint the look of the Occlusion material, Tint will only affect the material if an Env Map Color Map has been selected.
Env Map Color Map	If there is a path to a texture, than this map is used to calculate the occlusion using the map as a basis for coloring. See Environment/reflection maps for more information.
Env Map Space	The ray used to do the lookup in the map is transformed into this space. The fourth option in the menu will activate the Other Object parameter. See envmap for more information.
Other Object	Allows the user to manually select an object which will be used to determine the transformation space of the Map. See envmap for more information.

Surface Color

Use Base Color	Defaults to on. Controls whether the Base Color will be used as a global tint on the output of the material.
Base Color	This color is multiplied at the end of the material and is usable as a global tint.
Use Point Color	If enabled, the Point Color attribute (Cd) on the geometry will be used to tint the material. Disabled by default.

Color Map

Use Color Map	If this box is checked the Base Color is multiplied by the specified texture map. Defaults to off. If Use Base Color, Use Point Color and Use Color Map are all off, the surface color will be white.
Base Color Map	This the name of the texture file. The icon to the right opens a file browser.
Color Map Wrap	Determines what the texture looks like when the texture coordinates are larger or less than 0 to 1. See texture for more information. Repeat means the texture will repeat (tile). Streak means the texture color at the edges is clamped and streaks outside the map. Decal sets the color outside the texture map to the Border Color.
Color Map Filter	Type of anti-aliasing filter used. See texture for more information.
Color Map Width	Filter Width is the number of pixels, in both u and v directions, to use in filtering. See texture for more information.
Color Map Border	The color used outside the map if Decal Wrap is selected. See texture for more information.
Map Intensity	This is a float parameter which can be used to scale the effect that the color map will have on the color output from this vop. A value of 0 will provide a similar result to not using a map at all.