My model is a sitting humanoid. You can see a video here, which shows the problem perfectly:
The model is to be used as an enemy in a unity game. Those parts should be fixed in such a way you would expect it to look like if the missing parts were there.
Your brain already completes it, this is what the model should look like. I created an example outline on the right upper arm of the creature.
Example: arms are round. You only see parts of the arms, sometimes more, sometimes less. In an abstract way, arms are cylinders. So there should be cylinders as a rough guide along the fragments. As I wrote, your brain knows it already what it should look like.
My question also adresses the painting of the non-existing parts to make them match.
How do I fix the missing parts efficiently the way described, so it looks like a sitting humanoid?