關於無縫建模的接口問題！

[honeyyong]

本人用MAYA3.0進行無縫建模，用的方法是nurbs,象一塊塊皮膚一樣貼模，進行了規劃,方法是從"the art of maya" 中學來的，不過在進行最後的"global stitch"後全部的面是聯結在一起了，而且很平滑，但使用"attach surface"沒法把片面全部接起來，只能接上一部分，而且沒法用"close surfase"封口，實在很疼苦！

[stantang]

The method you used is so called "patch modeling". You should not (and won't be able to) use "Attach Surface" if you use patch model your model 'cause the isoplam of the edges won't match up. That's why we use "global stitch" to stitch all the patches together so that when you animate it, the seams won't open up.

[honeyyong]

很感謝你的建議，不過我在建模中已使用了"global stitch"進行接縫，而且每個面片的網格都十分匹配，"global stitch"也十分成央M但在渲染以後出現很明顯的裂縫，我也使用上了"鑲嵌細分""tessellation"但始終沒效，真沒辦法了。

[Stormtroopar]

Well, it could be a couple of things. Your parameterization has to match up between all your patches which you seem to have. Does all your patches have complete tangential continuity between each other? Stitch can help you make the surface tangent to each other (sometimes forcefully) but you really should do this manually and set it up correctly first before you do a global stitch.

One last thing is the tesselation of your surfaces have to be set correctly.

Here is a good explanation of how to set this up:
http://www.the-gnomon-workshop.com/tuto ... ation.html

You have to understand how nurbs work. If your surfaces have tangential continuity and tesselations are set correctly, even without stitch, you will not see cracks. Stitch is really to maintain the surface without crack together when deformed, skinned, or animated.

Hope this helps.

[stantang]

Completely agree! Make sure the parameterizations are match up. Normally, I would rebuild the patches to "0 to 1" parameterization and delete all the history before I stitch them. If you have to manually fix the tangeny between the patches, there are three very useful mel scripts called "mMidPointCvs", "mPlanarCvs" and "mAlignCvs" on highend3d. I can't live without them! hehe...

[Stormtroopar]

This is another script I always use when patch modeling as well:

tangentCVWin.mel

As usual, it is available at Highend3D.com.