Like EXR, so you can pull grays out of white without getting any clipping. Save in a format with a higher bit depth. I leave off exposure control, and do everything in post. There's a fine line of the product turning out too gray just so you can see the detail, or too white that it disappears into the floor and background.

One of the worst requests I get from clients is when they have a product that is white, and they want it on white. You may even be able to just use levels or curves on your character and/or are heading in the right direction. For quick stuff, you can get by with using just a couple passes to tweak your beauty pass. You don't necessarily have to do the traditional render comp where you rebuild the render with all the passes. But it will give you the flexibility to get a beautiful render on white with white parts on your character. There's much more to it than I could write about it here. Go through the documentation on Render Elements, and watch a few videos on render composting. Other render elements that will be useful could be lighting, total lighting, shadows, reflection, specular, and maybe even light select. Make your mask from this in your post processing app by selecting by color or channel. When you render, this RE will have your character as pure red. Select your character, right click, Object Properties and give it Object ID 1. The MultiMatteElement is a good one for this. Set up render elements that you can use to tweak the background separately from your character. Thanks everyone and sorry if this looks confused, I'm a bit newbie Someone can help me set up a scene like that? The problem is wihout exposure control and lights everything in a bit bright and the model vanishes in the BG.

This one is done without any exposure control, the other 2 has the physical camera one. This third one instead is perfet, if you put the white bg everything is merged, also the eyes (which have self illumination) actually look better. Same in this second case, there's no light or shadows here The background does not exist, but in the rendered it doesn't match the floor So I decided to add lights, but this is the result: I Thought I just had to place the floor and a white enviroment map, but this way I have no control over the scene lights and the model, which is white too, merge too much with the scene. I want my model, which I'm going to animate, to move in full white space with floor and few fornitures. I think I'm missing something with enviroment maps and exposure control.

Vray 3 rhino toon