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Trimming NURBS surfaces


show more Trimming NURBS surfaces provides you with in-depth training on 3D + Animation. Taught by George Maestri as part of the Maya 2011 Essential Training show less
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Trimming NURBS surfaces

In Maya, curves on surface can also be used to do what are called Trims, which allow you to trim away either what's inside or outside the curve itself. So let me show you how this works. So I am going to take a surface here. Let's just go ahead and take a simple plane, and let's go ahead and shade that. So if I want to, I could just draw a curve on this surface. All I need to do is just hit this Magnet buttons, make it Live, do Create, and let's just do a CV Curve.

Let's just go ahead and create a lovely heart shape. And I am going to go ahead and Close that Curve. Now, this only works with Closed Curves, because what you need to do is have an inside and an outside. So if you don't have a Closed Curve, there's no way to determine what's in and what's out. So once I have this, I am going to go ahead and turn off my Magnet and select my Surface. So now I have a surface with a Closed Curve on that surface.

So what I can do is I can use this to either trim away what's inside or outside of that curve. So I can do that by doing Edit NURBS > Trim tool. So what do we want to keep? Do we want to keep what's outside or what's inside? Well, let's keep what's inside and hit Enter. Now, if you remember from last chapter, we did this using what's called Make Planar. This is actually the same sort of tool, because what I have got is I have got my Surface, and I have got this Curve on the Surface, and really, all we are doing is we are just doing kind of a little rendering trick here.

We are just trimming away the parts of that surface that are outside the curve. And this is a great way to make irregularly-shaped NURBS patches. Now, remember a NURBS patch is always four sided. So you really can't shape it into something like this, but by using Trim, you can. And now if I want to, I can go into, for example, my Control Vertices, and again, this all sticks together, very similar to Make Planar. So let me show you a little bit more of a practical application for this.

We are going to go ahead and open our scene. It's called Scooter10. Now, this is the scene that we had, where we kind of placed all these curves on the engine housing of this scooter. Let me go ahead and move this away so we can actually see this a little bit more closely. So what I can do is I can actually use Trim to keep parts of this and trim away the other parts. So all I have to do is do Edit NURBS > Trim tool, and again, I am going to click on what I want to keep, hit Enter, and now, if you notice, I don't know if you can see this, I have got holes.

So now I have kept the outside and trimmed away the inside. So now I have this original curve here, and I can just duplicate that and use this to make -- so I am going to go ahead and select this Trim Edge here. I actually can right-click over this and say Trim Edge. So I am going to select this Trim Edge, select this, do a Loft, and now I have got kind of like an inset, so it looks like this has some thickness here.

And I can do that for all of these. And by using the Trim tool, I have cut out three holes, and then duplicating those curves and using a Loft, I have actually created some thickness for those. So the Trim tool is a great way to create holes or irregularly-shaped objects in a NURBS surface.

Trimming NURBS surfaces
Video duration: 3m 42s 9h 8m Beginner

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Trimming NURBS surfaces provides you with in-depth training on 3D + Animation. Taught by George Maestri as part of the Maya 2011 Essential Training

Subject:
3D + Animation
Software:
Maya
Author:
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