V-Ray Tip: Proximity Dirt and Wear Masks with VRayDistanceTex

Drive believable grime, mud, and wear automatically by using VRayDistanceTex to build proximity-based masks—no manual painting or UV edits required.

• Create a VRayDistanceTex node.
• Add reference objects (ground planes, walls, bolts, window frames, tire splashes) to its object list.
• Set Distance to the maximum influence radius (in scene units); this defines how far the dirt effect reaches from those objects.
• Use Color Inside = white and Color Outside = black for a standard “near = dirty” mask (invert if you want the opposite).
• Increase Falloff/Softness for a smooth gradient; a harder falloff creates crisp accumulation lines.
• Plug VRayDistanceTex into a V-Ray Blend Material (as the Blend/Mask) to mix a Clean base with a Dirt material layer.
• Optionally multiply the mask by a noise or triplanar texture to break uniformity and add natural variation.

Practical uses:

• Contact dirt where objects meet surfaces: feet on floors, props on shelves, cars on ground.
• Grime streaks below protrusions: windowsills, vents, and pipes (use helper meshes to define influence).
• Mud splashes around wheels and fenders by targeting wheel geometry.
• Localized wear on corners and edges by adding thin helper shells along edges as distance drivers.
• Dust buildup under furniture and behind appliances.
• Wetness or moss near floor-wall intersections and shaded zones.

Shading tips:

• Remap the mask with Color Correction/Output curves for precise contrast and thresholds.
• Layer with VRayDirt: multiply VRayDistanceTex (proximity) by VRayDirt (cavities) to get targeted, crevice-focused grime.
• Use VRayTriplanarTex for dirt textures to avoid UV seams on complex shapes.
• Drive multiple channels, not just diffuse:
  • Increase roughness where dirt accumulates; reduce reflection amount and add micro-bump.
  • Blend a dirt normal map only where the mask is strong.
  • Tint albedo subtly; over-saturation reads fake.
• For glass/frames, use the mask to raise coat roughness and add tinted streaks near frame proximity.

Performance and workflow:

• Keep the object list lean—only include actual influencers. This reduces distance queries and speeds up renders.
• Work to real-world scale; Distance is unit-sensitive and scene-scale dependent.
• For heavy shots or crowds, consider baking the mask (VRayExtraTex render element) to a texture/vertex color for re-use.
• In animations, VRayDistanceTex updates with moving objects; still, profile performance and cache/bake if needed.
• To export a dirt mask to comp, add a VRayExtraTex render element with VRayDistanceTex plugged in for clean AOVs.

Troubleshooting:

• If the effect is inverted, swap inside/outside colors or invert in a Color Correction node.
• Banding or harsh edges: increase falloff, adjust Distance, or add subtle noise.
• Patchy coverage: ensure reference objects fully cover the intended influence areas; add hidden helper meshes where needed.

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