UV Unwrapping

Section Summary

Key Learning Points
Unwrapping Process Overview
UDIMs
Tools & Learnings

Key Learning Points

Copping UV Data between meshs - ' Mesh>Transfer Attributes' was very helpful for updating the
Unwrap Meshes prior to repeatedly copying them - more of a reminder to self then a learning point but i forgot to do it this time then burned a heap of time rectifying my mistake

Unwrapping Process Overview

In general, the unwrapping process went relatively smoothly and easily due to the overall shape of the character and the distinct materials he’s comprised of.

First, I used a camera projection on the body to capture all the UVs and pulled them to the side of the U1V1 area.
Secondly, I created seams around each material transition—such as at the base of the neck where it shifts from leathery skin to white body feather fluff, as well as on the beak, legs, nails, etc.
Third, I cut along the back of any cylindrical parts of the body to allow for proper unfolding & hiding the seams out of sight where posible.
Fourth, I performed some cleanup where needed to reconnect certain areas of the shells.
Fifth, I grouped together shells with the same type of material, then used auto-align and distribute tools to place them into the appropriate UV spaces for the UDIMs.
Sixth, I adjusted some of the distribution manually, as the auto tools tend to be very conservative and can result in wasteful, inefficient layouts.

Face Unwrap

Since the model will mostly be viewed from the front, I attempted to minimise visible seams from that perspective. The large white unwrap on the left represents the face.

Head Side View

Because of the face and head being shaped like a large sphere, I had to add more seams than I would have liked in order to avoid stretching and deformation. This includes a seam under the chin and another around the neck to separate it.

Head Rear View

The seams on the head are primarily located along the back and the top of the skull. This area will mostly be hidden under the hat and is intentionally kept relatively plain without it, to prevent the seam from becoming too visible.

UDIMs

Although it's a bit more of a hassle to set up the materials again in the game engine or Maya, having spent a fair amount of time working with VR development, I've developed a strong focus on texture and memory efficiency. As a result, I personally prefer using multiple lower-resolution UDIMs rather than a single UV map. An added benefit of this approach is the ability to quickly apply generators to materials of the same type, ensuring that all instances share the same texture resolution and can store generated data as efficiently as possible.

Additionally, as seen in the feathers and fluff UV, all of the mesh UV mappings are aligned to best match the natural flow of the materials with the generated texture outputs.

Black Leathery Skin

Face & Feet

White Soft/Fluffy Body

Chest & Arms

Keratin Beak & Talons

Mouth & Nails

Feathers & Fluff

Wings and Joint Area Fluff

Other

Hat, Chain, Eyes, Tongue

Tools & Learnings

Copying UV Data - Feathers & Fluff

For the feathers and fluff, I forgot to pre-unwrap them before duplicating them multiple times. Additionally, I had the joy of manifold geometry spawning at some point due to a misclick with the Shift key. After cleaning up the meshes, I had to reapply the UVs to many of the feathers. Thankfully, I discovered that Maya has a useful tool for transferring UV data based on the component mesh. It worked really well, although I couldn’t figure out how to copy the UV data to more than one mesh at a time.

Apply Materials To UV Shells

Checking work via applying temporary materials
I applied some temporary materials to my UDIM-related UV shells. I believe Substance Painter requires them when separating out UDIMs, and it also helped ensure that all areas of the ibis character were properly unwrapped and accounted for with UV shells.

I found that I had miscut part of my shells, and the black neck material had an unsightly black tab/bib running down the chest of the ibis. This process helped me check my work and go back to rectify the issue, ensuring that the different materials better followed the natural edge flow of the character.

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