Thursday, April 5, 2012

Love Is a Many-Headed Thing, Part V

I hate snakes. They look like they might be easy to model, but actually, they are not. The external form of a snake is simple enough, but the inside of its mouth has enough hills and ridges to rival the Sierra Nevada. The worst part about modeling snakes, however, is texturing them. A snake’s body is covered with scales of such precise shape and arrangement that 3D artists will notice if the texture is shoddy.

Having finalized the snake’s mesh and mapped its UV, I began to make its normal map. Basically, there are two ways to do normal mapping:

  • You can create a high-poly version of your low-poly mesh and use both to bake a normal map in your 3D modeling software. I’ve discussed how to do this in 3ds Max elsewhere in my blog. You can also bake normal maps in the latest version of ZBrush, but if any part of your low-poly mesh protrudes from the high-poly model, that area won’t be baked. In 3ds Max, you can overcome this problem by adjusting the cage in the Projection modifier.

  • You can also make normal maps out of 2D images. This is usually done by using image editing software to convert a black-and-white height map to a normal map. I’ve tried using the nVidia normal map filter for Photoshop to do this, but frankly, the results are awful. Alternatively, with photography and some clever lighting, you can shoot images and convert them into a normal map, but in the case of my snake model, this is not a viable option for me.

When it comes to sculpting organic models, ZBrush and Mudbox are the software of choice. I didn’t want to fashion scales all over the entire snake, however, as this would be a monumental effort. Instead, I cut off the snake’s head and a section of its body and sculpted each separately. Because the model has mirrored UVs, I only need to sculpt the right half of each segment. My plan is to bake the normal map in 3ds Max and use Photoshop to replicate the baked texture in all other parts of the snake’s body. It won’t be easy to align each segment, but it still beats having to sculpt everything.

Here's what I have so far. The scales on a snake's head are roughly hexagonal and occasionally pentagonal, but as you move down the neck, the scales change to an interlocking set of diamond shapes. These models aren’t perfect, but I believe they will do.

I made so many mistakes while making the above sculpts that I had to backtrack too many times for me to recount. If I were any kind of sane person, I’d have gone mad by now from sheer frustration. As it is, I lost my mind a long, long time ago, and I haven’t missed it since.


Eguintir Eligard said...

I am electing to do the image method to texture project crocodile. The pattern will be somewhat repitious but I think with proper use of the clone tool I can make it a better effort than at least some of the stock nwn2 models. And that's good enough for me.

This whole process does sound much like how many redos I've done on my first model still to be completed. Kudos

Jclef said...

Looking good, bud - very nice work on those scales!