Using viewport shading as a cryptomatte

Cryptomatte is fairly important for compositing. We can use viewport shading “material” or “random” color to separate the objects, but the viewport render colors are unreliable (they become washed out). This is not ideal. The “random” color setting doesn’t have enough range and the colors become too close in value in order to be easily separated.

Material flat crpyto
issues: Can’t change viewport material color of linked objects, can’t set color for a collection

Random flat crypto
issues: Colors are too close, some colors seem to be the same as objects that overlap them
Solution: Increasing the range of colors (less pastel), ability to change seed for coloring

Viewport Rendering
I’m not sure what’s going on here. Seems like adjusting brightness and contrast after the render would be a hack more than a fix

Test scene

Material Flat

Random Flat (here we see blending of the props and backgrounds)

Random Flat rendered using Viewport Render (washed out colors)

Additionally individual stands are handled as separate objects. It would me more logical that particle systems are handled as separate objects instead. The randomness makes it impossible to color pick hair in post.


It would be good as an option, yes, however particles can be used for many things, such that sometimes it would be preferable for particles to be handled individually. In case of hair particles speciffically though, no option might be necessary, in that specific context it’s probably fine to just handle it as a single object, yes.