In Episode 03 of my Unreal Engine 5.6 building system series, I take what we already had (a build preview you can pop up and move around) and start adding the “can place / can’t place” feedback that makes a Valheim-style builder feel right. The main goal is simple: if you’re aiming at a valid surface, the preview goes green, and if you’re trying to place in the air or somewhere invalid, it goes red. To do that, I build a placement material in the material graph (grid overlay, tiling, emissive controls), then I show the difference between masked vs translucent and why I personally like the translucent look better for previews. After that, I wire the logic into my Buildable component: I create an enum for build preview status, loop through all material slots (so it works even if your mesh has multiple materials), and swap the material instance based on whether we can place or not. I also add cycling through buildables by updating the current preview index (increment/decrement with wrap-around), then updating the preview mesh from my data at that index. Finally, I add the first pass at actually placing the actor: only spawn when the preview status is “can place.” Next episode we’ll fix the obvious issue—preventing overlap/placing into other pieces—then we’ll move into snapping, grid, rotation, and Z offset stuff.