I had a good idea of what shape I wanted the paw (or at least its pads) to take on, after seeing this excellent tutorial by  Kenket

That pentagon trick really works and even my terrible 2D skills were able to grind out the top left sketch after only like 30 minutes! (I'm only sort of exaggerating; I am really bad at 2D.) Later, a quick 6 minutes yielded the grey shape mockup perfectly on the first smoothing attempt. Go figure :P

For there, the process was mired in terrible issues. I had forgotten just how incredibly fragile the balance, maintaining the quality deformation of the paw and its digits, is. Simple adjustments to positions throw everything out of alignment and require tons of skin weight painting. Worse yet, I simply could not come up with appreciable shapes once the model was smoothed.

The failures were innumerable (mostly because I use letters in my file name branching, not numbers). Two of the most prominent ones are pictured in the center. Well, mockups of them anyways. I'm only reshaping two of the digits currently, and will figure some way to symmetrically apply the shape to the other two digits, probably using Quad Draw. These mockups are Photoshopped to be symmetric so I can get an idea of how successful they will be, before putting all that effort in. I figured that part of the problem was I only had mocked up the paw pads, and so created a mockup to cover the shape of the paw, the pads, and even the nails. This helped give me direction, but I wasn't making progress on implementing the shape.

For a while, it looked like it would be impossible to get the final shape I wanted out of the smoothed model as it appeared I would need the unsmoothed shapes to be so big that they overlap and made proper skinning impossible. This led to a ton of skeleton experimentation, revealing the aforementioned fragile balance. It even highlighted skin weight errors on the initial shape/skeleton that I hadn't noticed before.

It wasn't until I was mindlessly spinning a joint in despair that noticed unusual deformation on the base of the left most digit pad (the edge near the paw pad) and realized that it couldn't be attributed to any of the joints I had been weight painting. It was the heel joint! I hadn't noticed it's overreaching influence (introduced by the previous week's 3 inter-digit joints connected to the pad.) When a new helper joint like these are introduced, it not only has its own influence, but can expand its parent joint's influence too! I hadn't noticed it before because all my lovely scripts for position joints snap everything into place and you don't see the motion that show the mistaken deformation.

Once that was figured out, a spat of new helper joints was added to the paw digits, to counter the paw pad joint's influence. This worked OK, but digit's joints were still influencing their neighboring digit's polygons. A couple more helpers on the two medial digits has all but eliminated this. There is still some cross-digit weighting but it's limited to the tip joint and I will just have manually paint them out. Every other attempt to remove them completely has made it worse.

With a somewhat workable binding skeleton, I was finally able to get on track with the paw shape. It is pictured in blue. It's not nearly as fantastic as the initial mockup, but it's progress. For comparison sake, I provided a final mockup of the blue current, using the same Photoshop process of mirroring the shaped side, adjusting it slightly, and adding nails. Unlike the green mockup, it does not use the grey mockup overlaid; it uses its current digit shapes.


*Phew* Reshaping the paw has been way more work than I thought and it's not even close to done yet!