Chaos Corona Forum
Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: arqrenderz on 2016-10-04, 16:49:50
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We have a funny discussion here at the office about what kind of materiales have anisotropy, I think that only raw metals and some types of fabric (silk) would have anisotropy, and my friend says that plastic laminate, wood, polished ceramic floors, and plastic laminate brushed surfaces.
Im always looking to improve my materials and if some one knows about this it would be really helpful
THX!
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AFAIK everything can have anisotropy if it's "brushed" (has tiny scratches following some specific direction).
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Based on the MERL scanned BRDFs, lots of materials do, even wood. And not only in way 3D software simulates it, esp. fabrics can have multi-directional anisotrophy ( like cross)
There is this research paper from Siggraph this year where you can compile yourself a code which generates PBR maps from two mobile photos (with and without flash) and it generates aniso map, one I have never ever seen.
They also include samples, so one can try to use them somehow and see what it does.
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We have a funny discussion here at the office about what kind of materiales have anisotropy, I think that only raw metals and some types of fabric (silk) would have anisotropy, and my friend says that plastic laminate, wood, polished ceramic floors, and plastic laminate brushed surfaces.
Im always looking to improve my materials and if some one knows about this it would be really helpful
THX!
depends on your definition of anisotropy, could be anything from "almost all" to "almost none". Anisotropy emerges when the material structure is different in one direction than from another - i.e. when you rotate random small part of the material, and compare to another random part of the material, then if you can tell the two parts have different rotation, the material is anisotropic. Now there can be a discussion about what scales are we talking about, what material properties must change (optical vs. mechanical), ...
I guess you are talking about the anisotropic reflection parameter in Corona/vray. That one is tricky, because it is typically used to simulate mesoscopic details (not really big but not really small). With advanced enough normal/bump map filtering Corona wouldnt need anisotropy parameter, because you would be able to simulate it with a fine bump map with the same efficiency - so by this definition you could say that no real world objects have anisotropy, because you can always replace it with bump. But there are still metals that tend to break in single direction, crystals that change colors based on rotation, and all that weird stuff ;)
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So what are the safe parameters for it, (does any one really use it for all material types?)
i saw some weird shadows when using it (it was at 0.39)
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I don't use that parameter at all, maybe it's my meshes fault, but I get more trouble with odd shading artifacts than it's worth. Bump often quite suffices.
It really only works correctly on frying pans from tutorials :- ).