Chaos Corona Forum

Chaos Corona for Cinema 4D => [C4D] I need help! => Topic started by: Ben on 2020-08-26, 18:13:55

Title: Dark Materials / PBR Reflectivity
Post by: Ben on 2020-08-26, 18:13:55

If I understand it correctly for a simple pbr workflow I am never to change the reflectivity of a material (always keeping it at 1.0 / full white except metals and liquids and such) and simply change the glossiness value / map. I am always struggeling to eyeball and set the correct values at this pointhere and now I have a situation with some dark materials where I completely fail to get a satisfying result.

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=30570.0;attach=132694;image)

In my recent example I have two very dark materials: There are the wooden benches on the left that should be stained black and there are the concrete floor tiles. Concentrating on the floor: If too much light is reflected normally I would just use a much lower value for the glossiness (here 0.1) which in a way works.

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=30570.0;attach=132696;image)

But if I compare real life images of a similar dark floor (concrete tiles like this are usually more polished) then the value should be around 0.60 to 0.70 I would say.

(https://image.jimcdn.com/app/cms/image/transf/dimension=330x330:mode=crop:format=png/path/s4550dfa23f43f200/image/ic0d30e3c0bb9b476/version/1472139573/image.png)

But the texture stays greyish and washed out + overblown.

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=30570.0;attach=132698;image)

The same counts for the wood more or less. It just doesn't look like black wood. So how do I takle this without changing the reflectivity or use a fresnel map in this slot? Am I making a mistake in setting it up or are these correct results under these circumstances of lighting and all? Any help appreciated.

Title: Re: Dark Materials / PBR Reflectivity
Post by: Beanzvision on 2020-08-27, 13:39:42

Hi, the lighting in the real-life image doesn't really match that of the render. So naturally, it will look darker. If there was a large opening and looking towards the light, the real-life image would most likely look like the render "gloss .7". You could try the skin shader and make use of the twin reflection channels? Here's an example of that.

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=30570.0;attach=132735;image)