It's hard to tell for certain from the paper, without going deep into the code, but it seems they created the new model the same way the depth conditioned SD mo

It's hard to tell for certain from the paper, without going deep into the code, but it seems they created the new model the same way the depth conditioned SD models were made i.e. normal finetune. It might be possible to create a "original view + new angle" conditioned model much more easily by taking the Controlnet/T2IAdapter/GLIDE route where you freeze the original model. Text to 3d seems almost close to being solved. It also makes me think a "original character image + new pose" conditioned model would also work quite well.