I know it's been some time since this build was released, but I recently loaded a new build of FRED after a bit of a hiatus and noticed that many ships are being rendered empty. After some experimentation I found that it wasn't empty, it's simply that come fighters with cockpits are having their cockpits rendered and nothing else. For fighters with additional submodels, turrets and special details, these are being rendered as well. I've also noticed on some larger, older models that are using tiling, certain textures aren't being rendered either. I can't specifically nail down the exact issue, but I have traced the introduction of this bug to this build. The March 7th build rendered properly.