i have a scene with displaced geometry that sometimes intersects refractive materials, leading to black areas where the interpenetration occurs. is there anyway in the shader of the refractive material, to count how many surfaces the ray has passed through, so that i could detect any rays that have passed through an odd number of surfaces and stop this?

i realize i could also fix the geometry, but still think this would be very useful.

Do you want to set max number of the Reflect and Refract rays ?
Is it your goal ?

If yes, you can define max ray's number with 2 way :

1.Define Max ray for your Scene via mantra Node

Mantra1 -> Shading -> Reflect Limit & Refract Limit

2.Define different Max ray number for each Object :

1.Select your Geometry Node
2.Open Edit Parameter Interface
3.In the For Rendering Tab find Refract and Reflect Limit in Mantra and add these to Exiting Parameters
4.Close Edit Parameter Interface and in the Geometry Node go to Render -> Shading -> Reflect & Refract Limit and set these parameters to different number

Check Attached file

thank you but that is not my goal.