Occlusion Displacement material

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

Displacement

Overall Scale

Controls the overall scale of the rough areas.

Displace Direction

This selector chooses how the values from the map or the nose are displaced.

There is no displacement where the map is black; Where the map is white; the displacement is away from the surface.

up & down:

There is no displacement where the map is 0.5 gray; Where the map is white; the displacement is away from the surface. Where the map is black; the displacement is into the surface.

down:

There is no displacement where the map is white; Where the map is black; the displacement is into the surface.

Displacement Map

Use Displacement Map	If this box is checked the specified texture map is used for the displacement. Defaults to on. If there is no map, there is no displacement.
Displacement Map	This is the name of the texture file. The icon to the right opens a file browser.
Disp Map Channel	Determines which channel from the map is used for displacement. By default, a luminance is done on all three channels.
Disp Map Wrap	Determines what the map returns when the texture coordinates are larger than 1 or less than 0. The options are: 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. See texture for more information.
Disp Map Filter	Type of anti-aliasing filter used. See texture for more information.
Disp Map Width	This is the width in pixels used by the filter in both u and v directions. See texture for more information.
Disp Map Border	The color used outside the map if Decal Wrap is selected.

Noise

Use Noise	Determines whether noise will contribute to the displacement effect.
Noise Type	Determines the type of noise that is used in the material. See turbulent for more information.
Noise Frequency	The scale of the noise pattern. Larger values give smaller, but not more detailed, patterns. Smaller values will benefit from higher Turbulence numbers. See turbulent for more information.
Noise Offset	This vector positions the noise on the object in x, y and z. See turbulent for more information.
Noise Amplitude	The bounds of noise function, in the case of original Perlin noise, -1 to 1, are multiplied by this value to determine the amount of displacement. Then this value is multiplied by the Overall Scale. See turbulent for more information.
Noise Roughness	This value sharpens or softens the edges of the noise. Lower values are softer, higher values sharper. Sharper edges may cause aliasing issues in motion. See turbulent for more information.
Noise Attenuation	This value shifts the median value of the noise. Values greater than 1, will dampen the noise down, whereas values less than 1 will sharpen the contrast between the noise values. See turbulent for more information.
Noise Turbulence	This value controls the amount of details in the noise. This is the number of times the noise function is called and summed. If the Frequency is high, there is no need for much detail, 1 or 2 should be plenty. This can effects the Amplitude of the noise as well since the summing will result in higher base values. See turbulent for more information.

Limit Mask

Use Limit Mask	If this box is checked, the Overall Scale is multiplied by the texture map in Limit Mask. Defaults to off.
Limit Mask	This the name of the mask file. The icon to the right opens a file browser.
Limit Mask Channel Select	Picks which channel of the texture is used for the mask. This allows using the one map for 3 masks. The default is lum which uses the luminance of all the channels in the texture as the mask.
Limit Mask Wrap	Determines what the texture looks like when the texture coordinates are larger or less than 0 to 1. The options are: Repeat means the texture will repeat (tile). Streak means the texture value at the edges is clamped and streaks outside the map. Decal sets the color outside the texture map to the Border Color. See texture for more information.
Limit Mask Filter	Type of anti-aliasing filter used. See texture for more information.
Limit Mask Width	This is the width in pixels used by the filter in both u and v directions. See texture for more information.
Limit Mask Border	The color used outside the map if Decal Wrap is selected. This should be selected based on the Displacement Offset.

Properties

Displacement Bounds

Usually tying this value to the displacement Overall Scale should work well. However making the displacement bounds as small as possible, without causing "rips" in the render, can lower render times. See render properties for more information.

Displacement Space

The space in which you specify displacement bounds. The default, "Bounds specified in object space" is the recommended value.

object Displacements occur in object space.
world Displacements occur in world space.

True Displacements

When running displacement shaders, whether the VEX variable P is actually moved (true displacement) or whether bump mapping will be performed.