Vray dirt to create markings on a ground plane

[stevesideas]

I have an object that is not visible to the camera and does not create shadows or generate any GI. This object is purely to create markings on another object below it. I have placed a vray dirt in the diffuse in the hope that it would create a fake vraydirt darkening on the object below it but I cannot seem to get it to work. I've tried adjusting the radius but without any luck. Any ideas ?

[stevesideas]

It seems I can't do this with the invisible object but I can add an extratex pass and comp the dark markings in post.

[joconnell]

Try distance tex instead maybe?

[tooves]

Yeah I have used VRayDistanceTex for this in the past. It works a treat as a quick mask for blend/mix materials.

[stevesideas]

Cheers. I'll test out this method.