Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: razermail on 2019-07-04, 03:00:39

Title: Material with transparent diffuse color?
Post by: razermail on 2019-07-04, 03:00:39
Hi everyone. I need your help with making a material with transparent (alfa) diffuse color. I need it for many products that have many color variations, and client wants to set their colors in Photoshop. So I need to make studio/packshot renders (on simple white background), with all reflection and self shadow information, but the diffuse color needs to be transparent (like an alfa). I searched the web but still have no bloody idea how to make such material. Any suggestions?
Title: Re: Material with transparent diffuse color?
Post by: maru on 2019-07-09, 14:15:14
I probably don't fully understand this request, but lowering Opacity will make your diffuse materials transparent (non-white in the alpha channel).
Title: Re: Material with transparent diffuse color?
Post by: razermail on 2019-07-09, 15:56:20
Yes, but this will also affect other properties, like self shadows and reflections becoming less opaque at the same rate. And I need them to stay fully opaque, and only diffuse color to be transparent.
Title: Re: Material with transparent diffuse color?
Post by: mferster on 2019-07-09, 17:10:57
Can you post an example image?
Title: Re: Material with transparent diffuse color?
Post by: razermail on 2019-07-10, 11:02:56
It's something like this - diffuse is transparent, everything else (shadows, reflections, ground etc) are visible, so in Photoshop I can put any color under it to create final, colored render.

(https://i.imgur.com/ZYemX0Z.jpg)
Title: Re: Material with transparent diffuse color?
Post by: TomG on 2019-07-10, 13:50:49
There wouldn't be a material to do that, I'd go with a post processing route with render elements (see https://corona-renderer.com/wiki/render_elements and
and the other two videos in that series too maybe), with a mask for the object on the relevant resulting layers in Photoshop (or whatever you are using for post). One thing, while this is fine for a sphere here, for an object with any surface shape, you'll be losing shading on the object that picks out the geometry/shape, so maybe it would be better to have a neutral gray diffuse and use Colorize in post?
Title: Re: Material with transparent diffuse color?
Post by: jms.lwly on 2019-07-10, 13:51:52
As above - a simple way to do this would be to construct the material as it would be with colour/reflection/shadow - and render out a Shadow and Reflect element, as well as some sort of mask/alpha for the object.

Then in Photoshop, mask out the object for filling (or render a matching image without the object at all) - and overlay the Reflect and Shadow elements as Screen (or similar) mode.

There's probably a more technical way to achieve it, but it's a start!