Solved! (I think). Basically, FImage is an uncompressed image and you can grab a pointer to the data stream which interprets it as the correct format (RGBA32F, etc.) and then you can write to those pixels. I’m not 100% done yet because I think somethings up with the build system, and when I include ImageCore.h the compiler is not recognizing IMAGECORE_API so it’s messed up, but I’m sure I’ll figure it out. Missing an include or something.