offset reflection

[muoto]

hello,

i would like to set up a material that has a normal reflection and a offset reflection to simulate a kind of "depth" in the material.
so the idea is to have a kind of double reflection, slightly offseted.

any idea how i could do this ?

Thanks !

[Morne]

how about a base material with a coat? (like car paint almost)
Use VRayblendmtl?

[muoto]

yeah a blend, but how do you create a small offset in the reflection ?
i would like to create some double-kind of reflection, but only with one plane, and not a box object with two materials (one reflection and one transparent+reflection)

[Art48]

Use a box and tick "reflect on back side" in material options, does what you want.

[muoto]

yeah but i was hoping to "trick" the effect to have a double reflection on a single plane, so without modeling a box (i will make a sketch, seems no one understands what i mean )

[Art48]

Well VRay is supposed to do physically correct stuff so you would need to hack it like you said if you want to use a plane only.
Maybe play around with a gradient ramp map as bump to offset the reflection (as in slightly turning the plane one angle via bump)

[Neilg]

i will make a sketch, seems no one understands what i mean

Everyone knows exactly what you mean, you're not even willing to put a shell modifier on the object. You could try using some strange bump maps in blend materials but it'd be a nightmare to control and I wouldnt limit myself to doing this on a single plane.

[Rens]

hello,

i would like to set up a material that has a normal reflection and a offset reflection to simulate a kind of "depth" in the material.
so the idea is to have a kind of double reflection, slightly offseted.

any idea how i could do this ?

Thanks !

Hello Muoto,

This is doable; you need to bend the normals towards or away from the viewing angle on one of the material layers. Normal maps allow you to modify the object normals directly so we will be creating an adjustment normal map. I can't upload any images now so I'll do my best to describe it to you.

1. First you create a VRayBlendMtl.
2. Create a VRayMtl for the base. Set this to Fresnel reflection with a diffuse colour (for example).
3. Create a VRayMtl for the blend layer. Set this to 100% reflective, no diffuse, no fresnel.
4. Create a Falloff map and set this to Fresnel and use this as the Blend Map. The Falloff map's Fresnel calculation isn't 100% accurate, but close enough.
5. Create a VRayNormalMap or Normal Map and plug that into the base material's bump.
6. Create an Output map and plug that into the normal input of the Normal Map from the previous step.
7. Invert the green channel in the Output map, so in the Output map enable Enable Color Map, set the Color Map to RGB instead of Mono, and for the green channel only set the first key to 1 instead of 0, and the last key to 0 instead of 1.
8. Create a VRaySamplerInfo map, and set it to Normal Vector, Camera, Unsigned.
9. Plug the VRaySamplerInfo map into the Output map.

That's it! Basically we're doubling the viewing direction normals, just green needs to be inverted. If you change the normal map amount slider in the VRayNormalMap you can set the strength, also you can invert the direction with it.

[Morbid Angel]

that's pretty creative

[Rens]

Thanks.

[muoto]

WoW !... gonna try this out !

[Macker]

What a great idea.

[muoto]

Great, works very well indeed. Thanks a lot.

made a small file for those who want to play : https://dl.dropboxusercontent.com/u/...reflection.max
(max2016/vray3.2)

This will be very usefull to simulate some depth on reflective materials (glass panel for instance with mirror on back face)