Octane Dirt Texture
Last modified: 10 March 2025The dirt map is a texture node typically used to control the appearance of intentional noise or dirt overlaid on a material.

Node Inputs/Outputs
- Strength: Controls the Dirt intensity across the geometry surface.
Details: Controls the Details intensity.
Radius: The relative size of the map set against the surface directly visible to the viewer. 100 will lead to almost complete coverage by the overlaying material.
Tolerance: Adjust the tolerance to avoid the black edges on roughly tessellated meshes.
Radius Map: Determines the proportion of the maximum area affected by the dirt texture.
Spread: Controls the ray direction with respect to the normal of the surface. A value of 0 means the dirt direction is shot in the direction of the surface normal and a value of 1 shoots the dirt rays in all directions.
Distribution: Forces the rays to gather closer to the surface normal. A value of 1 is the equivalent to ambient occlusion on a diffuse surface. A value of 0 gathers the rays in the normal direction.
Bias: Any non-zero bias will be used as the shading normal to sample the dirt rays.
Node Parameters

- Node Parameters
Strength:This is the value/lightness (0.1 to 10) of the overlaying material spread across the map.
Details: This is the density (1 to 100) of the overlaying material at certain angles as tiny specs of it are closely distributed across the constrained areas along the surface of the normal.
Radius: The relative size of the map set against the surface directly visible to the viewer. 100 will lead to almost complete coverage by the overlaying material.
Radius Map: Determines the proportion of the maximum area affected by the dirt texture.
Tolerance: Adjust the tolerance to avoid the black edges on roughly tessellated meshes.
Spread: Controls the ray direction with respect to the normal of the surface. A value of 0 means the dirt direction is shot in the direction of the surface normal and a value of 1 shoots the dirt rays in all directions.
Distribution: Forces the rays to gather closer to the surface normal. A value of 1 is the equivalent to ambient occlusion on a diffuse surface. A value of 0 gathers the rays in the normal direction.
Bias X, Y, Z: Determines the bias vector.
Bias Coordinate Space: Determines the coordinate space for the bias vector.
Include Object Mode: By default the mode is set to All, which considers all object intersections in the dirt calculation. If Self is selected, then only the ray-intersection with other objects is used for the dirt calculation.
Invert Normal: An added option to invert the normal and overlaying material.
Usage
The Dirt node has no color associated with it, so the Gradient 2 node is used to provide colour input as shown below.
The Gradient 2 node is used to provide colour. The Key Color inputs/parameters are used to set the Dirt colors.