Developer luxidea over on the LUXOPHIA GitHub account has quite a few 3D demos for Delphi FireMonkey featuring various techniques including Volume Rendering, Textures, Shaders, Materials, Polygons, Models, and more. If you are looking to work with 3D and FireMonkey this probably a pretty good place to start. The demos appear to be mainly targeted at Windows as some of them use some Direct3D features but others may just be straight FireMonkey 3D. You can check out a screenshot from each project below and then head over to Github to access the Delphi source code. The MyAsset project looks like a really good place to start as it has a plane grid and a sky map.

 

Volume Renderer - Learn "How to volume render a three-dimensional array."