- View Offline
- Understanding points, edges, and polygons
- Working with the Knife, Extrude, and Bridge tools
- Connecting splines
- Rounding corners
- Extruding paths from Illustrator
- Reviewing the polygon and spline modeling workflow
- Working with NURBs
Skill Level Beginner
There are going to be a lot of times when you're modeling in CINEMA 4D where you're going to want to be able to close holes and objects and there's a very special tool for that, that can be useful in certain situations ; it's called the Close Polygon Hole tool. I'm going to create a cube here, and let's make it editable and get into Polygon mode. Now, what I want to do is to just simply delete one of the polygons on the side of this object. So, let's hit the Spacebar to get to the Selection tool, and click on one of the sides of the cube and hit the Delete key. You can see that opens up the side of the cube, and creates this large hole.
If I right-click in the interface, I can go to Close Polygon Hole tool. When I hover over that cube side, it gives me the option to close it. When I click once, it closes up that hole. Now, that's really all there is to it. There is an option for the Close Polygon Hole tool, Create Tri-/Quadrangle. You want to generally leave that unchecked. Most of the time when you use it, you're going to be using it in a situation where you're going to close up a very specific polygon. One of the dangers of using this tool is when you're on an object like a sphere, for example, where you have to close up a whole bunch of polygons at once.
Let's see what that means. Let's delete that cube and let's go back to our sphere and let's make it editable. And we're here in Polygon mode already. So let's hit the Spacebar, get the Selection tool and grab some polygons and then delete them. Now, we're left with this hole and we want to use the Close Polygon Hole tool to close that up. If we right-click and grab Close Polygon Hole, and we hover over that, you see that it finds the hole just fine, but when we click it, we end up with this weirdly shaped polygon. That's an N-gon and that's no good.
In this situation, we want to be really careful about creating holes and objects like this. If we try on the Tri-/Quadrangle Button, you can see that's not going to do as much good. I'll undo that, and I'll turn that button on. And then when we hover over that hole and click, you can see that it made a bunch of triangles, but they're not really organized that well and still creates this weird dimple on the side of the sphere. If I undo that one more time, a really important thing to remember is that when you delete polygons, you're not necessarily deleting points.
So, if I go into Point mode, you can see all the points that made up those guys are still available to me. I can use those points to close that hole up in a very specific way. I can do that with the Create Polygon tool, and let's see how that works. I'm going to orbit around this guy so I can see some very specific points. I want to see these points right here. Let's right-click and get Create Polygon. Now, the Create Polygon tool works in a very specific way, and there's a rhythm to it. And when we're creating a quadrangle, in this case, we're going to go from these four points to create a polygon.
I'm going to go one, and I'm clicking one time on each of the points, two, three, and on the fourth one I go bum, bum. And I always do that even when I'm working by myself. I go one, two, and you have to be very careful about which points you're doing this on, three, b um, bum. Now, the reason I say you have to be careful, watch what happens when I click on the wrong point. I'm going to go one, two, three, bum, bum. It looks like I made the polygon in the right direction, but when I orbit around, you can see that, that polygon is actually stretched, and I clicked on a point that was on the inside.
So, you have to be really careful about which points you click on. That's why I'll orbit around so I can see that point isolated. Let's undo that and do it again ; one, two, three, bum, bum. Now, I can work my way around with the Create Polygon tool. One, two, three, bum, bum, one, two, three, bum, bum, one, two, three, bum, bum; I think you get the idea. I can go all the way around with that and close that sphere up completely. Now, one of the dangers with the Create Polygon tool is the idea of the normals.
And remember we talked about normals earlier. Normal is an axis that extends outward from a polygon based on the perpendicular angle to the surface. The normal direction determines the front side or back side of a polygon. Now, when you're creating polygons with the Create Polygon tool, you could be creating polygons that are facing the wrong direction. So, to find out, let's go to the Options menu and go to the Configure All, and under the Display options, let's turn Normals on if it's not turned on already. If we switch into Polygon mode and we select the polygon, I'm going to hit the Spacebar to grab the Selection tool.
You can see that when I click on those polygons, check it out, they are not facing the same direction as the rest of the polygons. You can see that all the ones that I created by hand are facing the wrong direction, and that can be really problematic when you're texturing or lighting. So, rather than leave those, what I'll do is select all the polygons and now I can really see which ones are facing the wrong direction. You can see if I orbit inside, there's those lines facing inward. I'll right-click and do a Align Normals. And that forces the minority normals to conform to the direction that all the other normals are facing.
So, both the Close Polygon Hole tool and the Create Polygon tool are really important when you're trying to close up holes in your objects.
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