Modeling a foot
| Original Version By: |
| Steven Stahlberg |
| Latest Version |
| LATEST VERSION |
I won't explain every detail in the beginning, you can get to the state in the next image several different ways. For example like this: polygonal box modeling.
This is the model I started with for this session - a simple model several years old that I'd previously used as the 0-level of a hierarchical SubD surface. But I wanted to rebuild it without the hierarchy.
The smoothed or Subdivided version:
Say we're going for realism. Well in that case this isn't working. It needs more detail, and for that we need reference. Also, the topology is bad. (I could make it better without reference, but I knew I'd need it before the end so I made it the first order of business.)
The best reference is without a doubt the actual human body, and I did use my own foot to some extent, but good photographs do have certain advantages over the living body (like for instance, my foot is really ugly). I used reference images from Peter Levius great site [www.3d.sk]- I found about 4 different women's feet there, from several angles, quite close up, flat on the floor, which was exactly what I needed. (I can't show all of them, for copyright reasons.)
The most important preparation you can do is sketching. First I sketched the major shapes I could see, then I sketched a preliminary topology. There's also a cross-section showing the spacing of vertical edges around the back of the ankle.
From here I started adding and deleting edges to the old model. On the left, the red lines indicate edges being added, and right underneath, the highlighted edges are about to be deleted.
A view showing some points being pulled to the left:
More edge-insertions and deletion steps:
At this stage I felt dissatisfied with the SubD version of the foot - it was still too smooth, and lacked detail.
One of the most obvious characteristics of the foot is it has much more detail than many other parts of the body. The contrast is especially apparent on women. It's also true of course for hands, knees, elbows and central/lower front of throat etc, though usually less so.
So I went back to the reference and did another round of sketches. On the left I've highlighted 'knobs' of bone and muscle that are visible most of the time, on most feet. On the right I've underlined the drooping shape of the ankle bone. Another thing I noted, which was unexpected, is that on some women the first knuckle of the index-toe - it's 'base' - is lower than that of the little toe.
With those knobs added:
And the final topology:
After conversion to SubD (no hierarchical edits):
A lot of people seem to think that polygons with 3 or 5 sides are bad when converted into SubD's, especially in other packages but also in Maya. The reasons given are usually that it creates bumps where you might want smoothness, and that the UV's may stretch. Perhaps there's also a sense that it takes a lot of effort to keep it all quads, and the resulting mesh has a more 'orderly' look to it, and that therefore it just has to be better. But personally I've never noticed any problems. As you can see above I've integrated triangles and 5-sides into my modeling method. It's a very easy way to add bumps and discontinuities, and keeps the polygonal model much lighter. In fact I find the slight chaos introduced by this method to look much more realistic than the overly clean look most CG has. It also works fine with deformations; here's a rigged foot bending:
In any case, they all turn to quads as soon as you apply the first level of smoothing to the mesh. Some other views:
Another rendering. This is rendered in the default Maya renderer, using depth-mapped spotlights.
- This page was last modified 05:49, 8 July 2006.
- This page has been accessed 10,598 times.
- Content is available under GNU Free Documentation License.
- About CGWiki
- Disclaimers
|
