Polished copper

[fraggle]

Hi, there are several matte copper, one circuit board copper, but no Polished copper on the library.
Also, I guess the matte one are sand blasted, so again it will be good to get some brushed one, like for the stainless steel request. Same goes to all metal in fact, such material finished are obtain mechanically, so they can't be perfect.
Perfection is easy to obtain in CG, imperfection is what CG artist are looking for, and that what takes time so setup.
Thanks

[Ivaylo Katev]

You can "polish" the mate cooper using the clear coat settings (may be we have to find a new name for this section). Set some IOR about 3-5, and set the "coloring" option to 1.
Let me to explain what these settings mean. The IOR gives the connection between the reflection and the angle of incidence of the dielectric (non metalic) materials. The perfect polished dielectric material has some small reflection (about 3-10%) , when the light is orthogonal to the surface, and this small amount of reflection is bigger when the IOR is bigger. When the light angle gets shalow, the reflection amount increases according certain law (the Fresnel law), reaching 100% for light barely touching the surface. The metal materials are not ruled by this law, or rather are border case. The pure mirror (polished conductive surface) is equal to a dielectric with infinite IOR, so we can represent metalic behavior by increasing the IOR up to certain value. The surface roughness of the metal acts like IOR modifier, and the effective IOR is still significantly bigger than non conductive material, but is not infinite, it's not even very big number. Feel free to experiment and to find the best value that you need. The second parameter "coloring" represents another difference between the metals and non conductive materials. The color of the non conductive materials is given under the surface of the material, i.e you need some volume in order to have color. Every one has seen thin sheets of colored material, the thiner is the sheet, the less is the coloring. However, is pure surface determined process, that's why the reflection of the dielectrics is colorless even for colored materials. This is not the case for the metals, they are conductive and this means their interaction with the light is a bit stronger, so unlike the dielectrics, the reflected light can be colored. The "coloring" parameter in the clear coat section controls exactly this ability, for cooper, gold, and another colored metals it must be some nonzero value. When we provide scanned polished material the value of this parameter is provided in the material, that's why it is marked with *, when you pick the material in the UI the proper value will be set. However, when you need to modify existing material like your case, the value must be set manually.

[fraggle]

Thanks, here is a test as well as the mat.
https://ufile.io/xovqq

I have to get rid of most of the Geometry in the metalball scene as it crash the GPU with a out of memory Ram usage (3Gb)