Arnold shader settings for reflective road sign

[heynewt]

I've got a night scene with car headlights moving past a road sign.  Can't seem to dial in settings that really capture that high reflectivity of road signs.   It's of course a specialized material with a narrow bounce back angle which is hard to replicate in PBR shaders.  Would love any suggestions.

[oliver]

That's retroreflection. As a brute-force-attempt i quickly set up a corner-reflector-array and did a test:

left: modeled corner-reflector-array | mid: plane | right: normal-mapped (baked from left object)

The modeled corners reflect the light three times, the normal-mapped ones do not.

Wikipedia: Corner reflector & Retroreflector

[heynewt]

That's a nice trick/workaround, but whoo boy, the number of polys that array requires makes it less than optimal.  Was really looking for a shader solution.

But thanks!!

[domo.spaji]

You can make copies of headlights and for that (copied) lights exclude everything but road signs and markings.

You would probably do that thru Arnold properties, I'm not using Arnold so don't know exact procedure.

In any case, it is simple effect and you need only diffuse component, like those objects are more lighten.

Don't want other type of reflections, that want be desirable in traffic.

[heynewt]

Thanks, that's a good suggestion.

Again, just thought there would be a shader rather than these good ideas for workarounds.

Robert