In other softwares I've used, I've been able to render out a black and white version of my scene or a solid color for all objects on alpha, which rendered at a fraction of the render time than I would rendering out the full beauty pass (I think I'm thinking of after effects), is there a way to do that in blender? or do I need to render out the beauty just to also get access to the matte?
Hi Andrew,
I don't have any experience with those other softwares, but you can switch the Render Engine to Workbench and get all sorts of superfast Renders, like greyscale, black and white, Objects on a Transparent Background and much more. Not sure if that's what you're looking for. And you'll still be needing a 'beauty' Render in order to use them as Mattes, right?
I've seen Kent in tutorials do it, but it's more like a hack than a Blender feature. And not for all the passes either, a black and white mask, a solid color, etc. I'm not so sure about alpha, but in the end, it all feels like hacks. Maybe there are addons in the Blender Market or Superhive that make that job a possibility.
I'm going off the top of my head, but if I remember correctly you can put all objects/collections into 1 collection or set all collection individually. All objects should be put in to a collection. Then in outliner click funnel icon and click the square with a circle cut out of it's center. This is the holdout option. If you used a master collection then click this icon next to that collection. If you are using multiple collections then click that icon for each collection. This makes all objects in the collection a mask/alpha shape. Then under rendering tab->film panel->check transparency. Then you can render out a moving matte. You can switch to eevee, but if the final render(aka the beauty pass as you call it) is in cycles you may get some anti aliasing artifacts. There is also another method using material override, but I don't remember where the setting are.