I was just wondering what I can reuse and not, and what the best way to do it is. So far I read that one can reuse materials and static meshes. But can I put them together in a Geometry and have several nodes all point to the same Geometry, and thereby show it multiple times with different transformations (because the transformations are on the parent node)?
And if I have several animated meshes, like monsters, I must have a seperate mesh and geometry for each, right? But they can have the same material?
Also, can materials be composed? I.e. can I have my standard colored texture material, and compose that with a transparent material, to get a transparent, colored, texture?
There is no real reason to share geometry. Geometry is mesh + material + transform. You can reuse mesh and material and you want to transform things differently anyway - creating new Geometry with shared mesh and material will be actually cheaper than having a separate Node for purpose of transform over top of shared Geometry (if it would be possible at all).
Materials cannot be composed directly. There is something called shader nodes, which will work a bit similar, but I don’t think it is ready for production use. Anyway, Lighting.j3md should be more than enough for your needs - you can configure it in many, many ways, no need for composition.