Simple version: Box with unlit material, you put your mesh, player pawn, light and make screenshot.
Bit longer version:
- make unlit material with color parameter exposed. Create instanced material out of it.
- make family of those instanced materials, or pick one color that none of your models has (for photoshop magic wand to apply alpha).
- create pawn actor.
- it should have camera, static mesh and lights
- create array of static meshes that you want tumbnails
- create array of colors for background if you need more than single color
- and maybe you need different light settings, so create array for lights and their locations etc.
- make keybindings and events for circling trough meshes, background colors and light setups
- make one extra binding for screenshot, there should be console command for it and there is node in blueprints to run console command
Run that “game” in some resolution that lets you create nice thumbnails (like 1024x1024) for photoshop. Then scale them down to desired size. Make screenshots, find where unreal saves them.
I did such thing for reflection cubemaps. I had blueprint actor that rotated self and made all screenshots.
Put as much as you can into blueprint, so it can be repeated with exactly same conditons (like lights colors, location of camera etc) it helps when you later discover some error and you want to make single screen without redoing them all.
Ps you can always do same during runtime with scene capture.