VRay for 3ds Max Manual

VRayDirt Map Parameters

	General
	Parameters

Search Keywords: dirt, AO, Ambient Occlusion, VRayDirt

General

The VRayDirt is a texture map that can be used to simulate a variety of effects, for example dirt around the crevices of an object, or to produce an ambient occlusion pass.

Parameters

Radius - this parameters determines the amount of area (in scene units) where the VRayDirt effect is produced. For further info, please see the Examples section. You can also use a texture to control the radius. The texture intensity is multiplied by the radius to calculate the final radius at a given surface point. If the texture is white at a given surface point, the full radius value is used. If the texture is black, a radius of 0.0 is used.

Occluded color - this is the color that will be returned by the texture for occluded areas. You can also use a texture map for this parameter.

Unoccluded color - this is the color that will be returned by the texture for unoccluded areas. You can also use a texture map for this parameter.

Distribution - this parameter will force the rays to gather closer to the surface normal. The effect is that the dirt area is being narrowed closer to the contact edges. For ambient occlusion, set this parameter to 1.0 to get distribution similar to the ambient lighting on a diffuse surface.

Falloff - this parameter controls the speed of the transition between occluded and unoccluded areas.

Subdivs - controls the number of samples that V-Ray takes to calculate the dirt effect. Lower values render faster but produce a more noisy result.

Bias (X,Y,Z) - these parameters will bias the normals to the X (Y,Z) axes, so that the dirt effect is forced to those directions. Consider that these parameter can also take negative values for inversing the direction of the effect.

Ignore for GI - this check-box determines whether the dirt effect will be taken into consideration for GI calculations or not.

Consider same object only - when on, the dirt will affect only the objects themselves, without including contact surfaces and edges. If off, the entire scene geometry is participating for the final result.

Invert normal - this option allows to revert the effect with respect to surface normals - e.g. instead of crevices, open corners will be shaded with the occluded color. See the Examples section for an example.

Invert normal - this parameter will change the direction of tracing the rays. When it is off the rays are traced outside the surface, when on they are traced inside the surface.

Work with transparency - when on, VRayDirt will take into account the opacity of the occluding objects. This can be used, for example, if you want to calculate ambient occlusion from opacity-mapped trees etc. When off (the default), occluding objects are always assumed to be opaque. Note that working with correct opacity is slower, since in that case VRayDirt must examine and evaluate the material on the occluding objects.

Exclude - allows you to disable the calculation of the VRayDirt map for specific objects. Excluded object will always be rendered with the Unoccluded color.

Result Affect - specifies a list of objects which will affect the calculation of the VRayDirt map. Excluded objects will be considered "invisible" for the calculations of the VRayDirt map.