Controlling detail with Remove and Cut

One of the advantages of Polygon Modeling is the ability to interactively add and remove detail. In this case what I'd like to do is flatten out one side of this cylinder here, and I can do that by removing edges. I'll go to the Edge sub-object mode, and click on some of these edges with the Ctrl key held down. Once I've made my selection, I'll want to tumble around, or orbit around, to the other side of the model, to make sure I haven't accidentally selected any of the back edges.

There we go, I've got those edges selected. Now if I press the Delete key on the keyboard, I'll actually punch a hole in the model. If you delete an edge, you'll delete the associated polygons that are touching that edge. That's not what I want here. I'll use Ctrl+Z to undo that. Instead I want to remove the edges and leave the polygons there. I can do that from the Edges panel here and you'll see Remove. If I click that, then those edges are all deleted and the polygons are left.

However, if you orbit around and look carefully, you'll notice that the curvature there hasn't changed. And the reason is, that although the edges have been removed, the vertices are still there. If I go into Vertex sub-object mode, you'll see that those vertices are still there. Now I could select them and delete them in a second pass. But that's too much work, really I can do this in one step, because 3ds Max will allow me to remove edges and their connected vertices in one command. I'll undo that, go back to Edge Selection mode, back to Edges, and if I hold down Ctrl when I click on Remove, that will remove those edges and their associated vertices.

The keyboard shortcut for that is Ctrl+Backspace. That's a very useful one that you'll use quite a lot. Okay, so that's been cleaned up. But the tops and bottoms here still have curvature. What I'll want to do here is remove these vertices. I'll go to Vertex sub-object mode and select these vertices with the Ctrl key held down, and press the Backspace key, and now those vertices have been removed. However the surface isn't flat, as you can see, if you orbit around.

What I really want here is a flat quadrilateral polygon here and a flat triangular polygon up here. All I need to do here is use the Cut tool to create a new edge. The Cut tool is found in the Edit panel, and in fact, you can be in any sub-object, or even Object mode, to access the Cut tool, and it looks like a little scissor. I'll activate that. And then as I move my cursor around you'll see that the cursor icon will change, because the Cut tool actually has snaps built into it.

So I move my cursor over to one of these vertices until my cursor changes to a small crosshair. I'll click on that once. And then as I move my mouse around, you'll see I'm getting a preview. Then I'll go over to this other vertex and make sure that it's snapped, click again to complete that operation, and to exit the Cut tool, I'll right-click in the viewport. All right, so there it is, I have created a nice flat surface there. And I can repeat that process down here if I need to.

I'll right-click to exit the Cut tool completely, select these vertices with the Ctrl key held down, press Backspace to remove them, and then go back to the Cut tool and chop a new edge through there, and right-click a couple of times. And there you go! I've used Remove and Cut to change the structure of the model.