Wood anisotropic reflection


(Konrad Kobayashi) #1

Hi–

wood has an anisotropic reflection compontent as seen here:

or in this vrscan material:

does anybody have an idea how to recreate this effect in Vray? it`s not quite just the spec. reflection – more like a deeper layer with an almost metallic shine.

Thanks!

further reading:

arroway texture anisotropic

Measuring and Modeling the Appearance of Finished Wood

Anisotropic Materials Appearance Analysis using Ellipsoidal
Mirror


(Konrad Kobayashi) #2

here is my try: sadly doesn’t look too convincing …

Bereich_372 Bereich_369

spec. pass:
Bereich_370


#3

If materials have a deeper shine than I call it pearl effect for me. I use it often, also for plastic materials to get a more lively look.

Here I tried it with wood, maybe it goes in the direction your are looking. Right sphere is with pearl effect. Per reflection color of the metallic layer you can control the pearl effect intensity. I use a b&w map at the rotation slot to avoid a homogeneous brush effect.


(Konrad Kobayashi) #4

thanks based on your example i tried to replicate it with vray 3.6:

spec. pass:

method:

vray blend material with “metallic reflection wood” + perfect reflector for lacqure layer mixed with fresnel map

blend mat:
Bereich_375

mirror mat:

basewood:

probably this is all (physically) wrong - idk

btw @micha: grüße aus berlin :wink:


#5

Hmm, your material is quite complex and I’m not so happy about some parameters. :wink:

I think, you could work with a single material and use layers there. I would use simple layers, no BRDF. So we could better kept the overview.

  • On the top a fresnel reflection layer for the clear coat.
  • Below the metallic reflection layer, visibility controlled by the opacity color (fresnel texture disabled). I set a low gossiness and an anisotropy. After some more testing now I found that we get a nice effect per rotation map (a soft b&w version of the wood). Now, it doesn’t look like homogeneous brushed metal anymore. :slight_smile:
  • At the low end the basic diffuse texture.

I think, the key for a good looking aniso wood effect is to find the right map for the rotation control.

Yesterday I observed a fish bone pattern wood parquets and there was a clearly visible nice aniso effect. So, for high end quality wood parquets viz this kind of setup could be great. Here a nice photo example. The aniso effect cause the dark and bright row look.

Grüsse aus Radebeul,
Micha

Here the complete Rhino 6 scene with maps, download valid until 13 dec 2018. I create a fresh material setup at VfR3.6.

right material with some metalic brush effect and mapped rotation control

This is the map for the rotation


(Konrad Kobayashi) #6

wow- really nice. exactly what i was looking for! now the wood doesnt look like painted plastic anymore!


#7

It was an interesting challenge to find a way. :slight_smile:


#8

Thank you, guys, this is super interesting to follow, I might come up with a material question some day too.

What are anisotropic reflections anyway? I get that base wood reflects light differently than glossy varnish on its surface, but that’s where I lose my ground.


(Andrea Montis) #9

Anisotropic reflection happens when the material structure is different from a direction than from another.

Wood fibers direction cause this behavior… so you can obtain it adding a proper bump/normal map instead of the anisotropic options.

The anisotropic option are more suited for brushed metal and micro bumps that are really difficult for v-ray to sample at really small scale.


#10

And visual it means, reflections are stretched in one direction, for example like at this old test here. At wood the direction of the fibers isn’t so homogeneous.

Interesting for wood and moon stone is, that the upper surface can be polished or with a clear finish, so that using a “brush” bump wouldn’t the right way since it is an “inner” effect. For brush metal it works.

aniso reflections

aniso reflection by bump only


(Konrad Kobayashi) #11

look at second 13. The right wood exhibits a reflection property not achievable with just diffuse+reflec./glossmap+bump. It reflects light on a deeper layer in a directional non-uniform way (anisotropic). How to replicate this effect was the orginal question – thanks micha again for an awesome answer.