Hello list, I'm currently working on a Gem patch where I have a lot of sphere primitives and I would like to identify the sphere that appears under some particular Gemwin screen coordinates (aka raycasting). I can't find an object that already does this calculation so I ended up finding this SO answer explaining the raycasting principle https://stackoverflow.com/a/19153090. Still, I'm a bit lost and don't know where to start ... I found this informative post for the 3D graphics noob that I am : https://gamedev.stackexchange.com/a/178645 But I can't figure out how to apply this to Gem. Any help would be greatly appreciated. Best, Joseph