Join George Maestri for an in-depth discussion in this video Converting NURBS to polygons , part of Maya 2011 Essential Training.
- View Offline
When you model in NURBS, a lot times the reason you're doing it is to get a very smooth flowing surface. But there're times when you want to convert NURBS surfaces to Polygons. So let's say, for example, you're working in games. Most game engines don't accept NURBS. They accept polygon. So you'll have to convert your models to Polygon. So let me show you some techniques for conversion. Let's go ahead and take a very simple NURBS object and convert it. We convert under the Modify menu. So we go Modify > Convert, and we're going to go NURBS to Polygons.
So now there're a number of options here. Let me just go through these. Now, how you convert a NURBS to Polygon really depends on the type of surface and your desired result. So we have a bunch of different options. So first of all, what do we want to output, or what's our Tessellation method? In other words, how do we convert a NURBS surface to Polygons? Now remember, a NURBS surface is a mathematically-defined surface. And so how are we going to tessellate that, or break that down into discrete Polygons.
So we can output Triangles or Quads. I typically go for Quads. And then we can do several different Tessellation methods. So if we go General, this actually tells us how much detail we want. So, for example, if we want Per span number of iso parameters on U and V, this will actually convert that. So for every one of these, we'll have three Polygons. So when we do Tessellate, you'll see how for each one of these we get three.
But this is also polygonal. So you're going to have hard edges between those. Do this one more time. Let's go Convert > NURBS to Polygons. And let's do another option here. The other option would be just Count. How many Polygons do we want? Now, this is great for game engines, because sometimes you would just have a hard limit as I can't have more than x number of polygons. Well, you can just say well, this cannot be any more than 200, and you rock.
Our Standard fit, basically what this does is it allows Maya to determine how many Polygons based upon the curvature of the surface. So if you have something that's broad and flat, it will have very few Polygons. If something is really tight and needs additional detail, it will add in that detail. So let's go ahead and do that. So you can see how for this, that works. So if now actually were to modify this, and, for example, added in some curvature here -- in fact, if you want, you can see how this is live.
So if I do Wireframe on Shaded, you can see how it's adding in detail right here as the curvature changes. So that's basically the more of the smart tessellation. Now, this may not give you the regular tessellation you want. But it will give you the most accurate and the most efficient type of tessellation. So let's go ahead and delete this. And let's select our slightly deformed sphere here. And let's do one more Convert and show you the last option, which is by Control points.
And when we Tessellate that way, all it does is basically just every CV -- in fact, let's go ahead and take a look at the Hull. Basically what it does it just takes the Hull of the object and converts it to a polygonal surface. So for each one of these squares, or quadrilaterals in the Hull, it creates a polygon. So those are some of the ways to convert NURBS to Polygons. Now, the method you choose really depends upon what you what your desired result to be.
Do you need a very specific number of Polygons? Do you need your polygons to be in a very specific order? Those are decisions you're going to have to make as you do the conversion.
- Getting familiar with the Maya interface
- Organizing scenes
- Creating hierarchies
- NURBs modeling for solid objects
- Adding color to models
- Applying bitmap textures
- Working with mental ray materials
- Polygonal modeling for characters and organic objects
- Deforming with the Skin tool
- Setting up lights and cameras
- Creating realistic effects such as depth of field
- Working with the Timeline
- Creating animation cycles
- Batch rendering
- Rendering with the mental ray engine