I think one of the biggest issue I've had with AP400 (RBX/UE5) was to translate the various designs I've made without proper character sheets into textured 3D models. Most of the time, I only use what I have in mind to create the models and textures, instead of proper references/artwork I have made in the past 

One of the good example of this is Valerie's PSX 3D model for AP400.

The issues with previous versions of that model were in the body and in the face texture.

Her shoulders were too large, her arms were too large for her supposed "physical weakness" of not being able to lift more than 4Kg (yes, that's in lore).

Thankfully, there are plenty of official artworks of Valerie, as she is probably the most depicted characters in all of Project Bad Apple.

I've recently done many changes to the (still Work In Progress) model, with her arms now thinner, her shoulders correctly sized, and her face completely changed

Obviously, because her medical eyepatch has ties to the story, it is an optional thing in her model.

However, because she is a Project Bad Apple character, and I have no plan in making her appear in the prequel AP400, this exact model moght be scrapped as she will have a higher quality model for her appearance in the main game.