Reflection help | UArtsy

Reflection help

2 years ago

no problem man. We can all help each other :).

One thing I have noticed that David does though is he actually uses a constant value for metalness then uses a lerp node to define the value of min and max roughness and masks this by using a greyscale texture in the alpha channel of his diffuse.

Quite a nice solution actually because it means he's using less texture maps

Nice explanation Vi! i understand it better! Thx!!

Great reply Vi! Thanks for that! From reading that and looking at my image again I can see my roughness map needs to be inverted!

With regard to the reflection captures, are they just on in the background and not cooked into the material in any way?

Which time zone are you in? I'm going to do some more work and then possibly a hangout later?

You're british right? Let me know if you need further explanation and we can do a google hangout or something.

Anyway. Unreal 4 uses a system called physically based rendering which is different to what was used before. I.e. diff, spec, gloss.

This is a good read for it if you want more information but I'll try answer your questions here.

So firstly the metalness map defines how metal a material is. White being really metal such as chrome and black being a non-metal like plastic or dirt.

The roughness map determines how rough a surface is, that is, the rougher the surface is the less reflective it is. In unreal 4, black actually means it's more reflective, i.e. no roughness like plastic or glass whereas white means it's really rough. Like rock

Both of these maps work together and you can define different materials on the same map. E.g. say I had plastic and steel using the same textures. So plastic would have a value towards black on the metalness map because it isn't a metal, but I still want it to be somewhat shiny so on the roughness map I would also put a value towards black which means barely any roughness so using this I would get a shiny plastic.

So for steel, I would have a value close to white on the metalness map which says this material is metal, and on the roughness, I would perhaps put it kind of half way between mid grey and black because even though it is somewhat reflective the surface is not completely smooth. So giving it a value that is not black means there is some roughness to it.

Lastly to use the sphere reflection captures you rebuild the lighting. To get accurate results you'll have to create a second uv set for the light map which Dave does in week 5.

Hope this helps and sorry for the long post! :)

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