Nurbs: resulting surface dependant on display level?

[Undseth]

Im sure the rendered object is unaffected by the display settings in the attribute editor.

Only the tesselation tab in the object's attrubute editor should affect the resulting rendered "quality".

[Studev]

undseth is right,

The NURBS smoothness in maya rendering is depend on tesselation in your attribute editor. Most of the times, i will use advanced tesselation rather than the normal one.

Best Regards
Studev

[kiri]

thanks. i was actually wondering about the actual construction of the surfaces, rather than the rendering of them. But i think the display level must not effect this (?)

also, i am aways getting the following warning when performing trims:
// Warning: Trim: changed to keep originals on; curves on surface have construction history with the dependency on the surface itself. //

can someone tell me what it means exactly? could it be the reason why the trims i am performing end up being not perfect trims, but leave over fragments of the trimmed surfacE?

[Undseth]

My mistake :D

Not sure about the warning. Could be just a reminder of sorts.


Regarding the mathematical stuff about your nurbs curves and surfaces, this cannot be altered in any way by the display settings as far as I know.

You have to work out the parametrization and any tangencies with the tools and some wit. This parametrization "thing" is somewhat mysterious to me.

Although, I have the impression from stuff I have read, that you "should" want to rebuild your nurbs surfaces to get an optimal/proper nurbs curve/surface. Not always neccessary though. But I think an "bad" parametrization in a nurbs surface may result in "bad" tangencies between nurbs surfaces, when using the tools for creating tangencies.

Else (about tangency) you can do this manually by aligning (not only the two end cv's on each of the two surfaces) the four cv's on the two surfaces so they form a straight line (two on each surface, the last and the second to last cv).

Hmm I have to learn more aobut this.

[kiri]

thanks undseth,
i cant say im any more enlightened, but it was interesting :)

let me know if you end up finding out more about it:D

[Undseth]

Changing the display level "say hitting 3 on your keyboard", does not alter the nurbs surface in any way, but it may show some more isoparms to snap onto and such, in the successive modeling process.

Im sure that any trimmed surfaces are unaffected as well by the display settings.

I think this answers your question. :D

[kiri]

yep, thanks :)
its the same as i thought, but i wanted to check coz my surfaces are yukky :( and i searching for why

[Undseth]

Hehe now you got me curious.

What kind of problem do you have with your nurbs surfaces?

[kiri]

well i performed a number of trims on a surface, and where i made the trims has all these bits overhanging where it should be a nice hole...
i tried rebuilding the surface, which helps, but doesnt fix it completely. And thats on a fairly high setting (i put extra 25+Vspans).
if i try to put spans on U direction as well, the shape of my main object changes to curvy on one side...

the 2nd problem is that even no matter how much i rebuild, the surface has a weird dark shadowy 'quality' all over it.
it shows up on rendering too... and its not just poor lighting.

hmm, i guess it must be hard to imagine, shall i try to post a pic ? ;)

[CGTalk Moderation]

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.