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jordanimation
05-24-2010, 04:59 PM
Hey guys, I've been working with polygons for like, 3 years or so. Today I thought I'd try my hand at NURBS modeling. I'm having the following issues.

http://s526.photobucket.com/albums/cc349/jordanhess/?action=view&current=blackarea.jpg

I started making a canoe, if you can see in the center there is a black region. Sometimes it renders and sometimes not. I have no idea what to do about it.

Also I was wondering why it does not render smoothly.

http://s526.photobucket.com/albums/cc349/jordanhess/?action=view&current=faceting.jpg
Dare-o
05-24-2010, 06:37 PM
Im pretty sure when you get those black areas its something to do with the normals, but im unsure how to fix it because i dont know nurbs that well. You can try changing the surface direction by going to edit nurbs > reverse surface direction. Maybe there's a stray CV in there somewhere? Try deleting it if you can, or merge them.

the faceting is from the render engine, use mental ray and it should fix that.
thehive
05-24-2010, 06:57 PM
you may have to rebuld the surface an up the isoparms, also in the render settings for it as well may need to up the tessellation.
ThomasWright
05-26-2010, 07:54 PM
For the advice you're looking for: It looks like the normals aren't blended properly between the two surfaces. You may have to find a way to re-smooth the normals.



Having said that, Nurbs is the Latin of the modeling world. By that I mean, it's a dying 'language'.
In college it was inflicted on us in the first week so we'd appreciate just how fast and easy it was to model from box polygons.
I'll be honest, the last confirmed case of Nurbs use in a professional production was Lord of the Rings for Gollum, and even then, they'd converted him to Polygons by the end of production.
Now I may very well be wrong, and if I am, someone feel free to correct me...but I think it would be a better use of your time for you to resume polishing your technique with Polygons.
KevBoy
05-27-2010, 07:45 AM
It your output is digital, polygons seem the norm.
If your output is analog, nurbs seem the norm.

Nurbs have the advantage of being mathematically smooth so that when you use it for driving a robot, or a 3d printer, it will not look degraded. Polygons only look smooth because of normal smoothing, which is a light trick that won't translate to the real world. Though for 3d print, a nurbs model will get converted into an .STL polygon file but that is only as a final step, not for its initial construction.
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