Can Someone Explain Workflow For Texturing Nurbs Surfaces?

[tonyhaer]

I've noticed that nurbs surfaces don't texture in the same way as polygons with UV mapping techniques. Can someone give me an example on how they would go about texturing a nurbs surface?

[gmask]

Nurbs automatically have UV coordinates which is cool .. the difficulty is when you have a nurbs patch model that you are trying to texture like a "pelt".

So I guess it depends on what kind of model you have that is nurbs.

[joojaa]

QUOTE(gmask @ 02/16/09, 07:56 PM) [snapback]300999[/snapback]
Nurbs automatically have UV coordinates which is cool ..

Yes because theya re basically 4 sided pieces material its easy to generate a perfect uv map form the chord length info. It is however as pointed out not as easy if you have 2 nurbs pieces. In any case the situation is very like having normal uv map pieces. But yes you basically use the texture reference thing in conjunction with projections to do tha same as with polygons. If thats something one wishes to do offcourse, lots of reasons NOT to.

[tonyhaer]

can you suggest some reading material or preferably video tutorials about basic texturing polygon and nurbs would be good.

[joojaa]

hmm... why do people ask that? I mean there's LOTS of tricks regarding this. And whan i say lots probably enough things you could do keeping you glued to the monitor for the rest of your life. What you really should do is understand what the data is. Then you can with moderate use of brain deduce the rest.

So what you od is make any nurbs surface attach a shader that draws out a simple uv ramp and try to deduce what it is you think would happen. Then make it work like you tough it would.

Anyway texturing is NOT about uv ordinates, its just uv layout. Texturing is about placing textures right. And texture coordinates mean NOTHING to the end result honestly. As long as theres uv of one kind that doesn't overlap i can generate all other possible uv fields form that.

[gmask]

QUOTE(purplemonke @ 02/17/09, 09:14 AM) [snapback]301069[/snapback]
can you suggest some reading material or preferably video tutorials about basic texturing polygon and nurbs would be good.

I'm still waiting to hear what you are modeling and why it's gonna be in nurbs.

[gmask]

FYI you could probably pick up any used copy of Inside Maya (insert old version number) and get some info on texturing.

[tonyhaer]

Hi thanks for your responses, incidentally i am doing character modeling and i want to know how you go about creating complicated textures like multilayered skin with veins etc... and position them correctly so they deform right. I really just would like to know what your workflow would be when you did something like this. Do you create a psd texture or do you use some external app or do you use the procedural textures??? and then do you break up the geometry and apply a texture to each piece or a global texture to the entirety of the model. Please bear in mind i know nothing really about UV's so can you tell me in layman's terms?

Thank-you for your help by the way

[gmask]

Well there are alot of options there.. but firstly I'll say that as far as I know.. nobody is using nurbs for characters at least not for the finally rigged model. The best work flow in most cases is polygons and then either convert that to sub-d's or let the renderer do it for you which saves alot of memory and time.

If your model is one big seamless creature then you can do what is called pelting. There are scripts for this. Basically what this does is layout out the UV's so that it looks like a skinned animal hide and then you can paint on it via any method you choose.

If your character has obvious sections like a robot or a clothed character then you could make a texture for each piece as you see fit. Although games character tend to use one mapped texture for all pieces wether it is seamless or not.

You can use procedural textures but that'll only get you so far. However if that's all you need then you don't need to make UV maps because you can create a texture reference object of you character and then the texture will stick to the rigged character.

Essentially UV maps refer to a 2d coordinate space. They could have called it an XY map but they didn't .. as far as I know the U & V are arbitrary and mean nothing specifically.

Best way I can think of to explain how to use them is to think of dressmaker patterns.. google dressmaker pattern. They section out the surfaces so that they lay flat.. well just image those section laid out on a large square and then you are looking at a UV map.

[joojaa]

Or projections.

U and V are the names of the underworld of the projection they could be called anything really*. but so could x y and z (but they have been arbitratily choosen to be last.)

Matematichians have this all explained in most books on calculus. Cant remeber what this kind of mapping was called. Its basically so you can do parametrican traversal of the surface. As a surface is 2 dimensional so will the mapping be, so its then spanned up into 3d.

Anyway i think your thinking the problem upside down. Its the job to generate and manpulate underworld your texture needs not the other way around.

*but incidentally U is just 3 steps away form x and its practical to call underworld U and you practically can have 3 dimensions of coordinates in most underworld application. So the surface normal corindtes for textures are called UVW.

[tonyhaer]

Thanks for your responses guys think i might have a go at pelting, incidently how do you go about converting polygons to subd's at render? is there an option in mental ray?