How can I snap a vertex to where two edges intersect?

# 1 18-05-2014 , 07:31 PM

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How can I snap a vertex to where two edges intersect?

I have an edge intersecting another edge. One of the edges has a vertex on them. How can I snap it to where the edges intersect? Or how can I create a vertex where the edges intersect? Maybe I can somehow do it with booleans but I'd rather not, they're kinda glitchy. Thanks.

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# 2 18-05-2014 , 09:11 PM

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you can use the "Snap to Curve" to do exactly what you're after. Select your object/vertex then hold down the "C" key, and middle mouse drag your vertex to your edge.

Also if you want to place a vertex you can use the split polygon tool and place it where you need it then press enter.

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Last edited by jsprogg; 18-05-2014 at 10:07 PM.

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# 3 18-05-2014 , 10:15 PM

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It's not working, not sure what I'm missing. Is this supposed to work between two separate objects that I combined?

I have snap to curve on. I select my vertex and go into the move tool. I hold down the the C key and middle mouse drag the move handle. Is that what I'm supposed to do? It's not working. Thanks.

edit: or is there a way to make split polygon tool snap to where the edges intersect?

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Last edited by madwh; 18-05-2014 at 10:18 PM.

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# 4 18-05-2014 , 10:25 PM

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Maybe you should describe what the end result you are trying to get is because from the screen shot even if you did suceed in snapping that vert to the edge of the other box you'd create a form of bad geometry called non-manifold. Any further operations within Maya on non-manifold geometry will have unpredictable results or just plain fail.

Are you simply trying to combine those two shapes into a single piece of geometry?

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# 5 18-05-2014 , 10:27 PM

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I'm just trying to make 2 books on top of each other and trying to delete the bottom of the book on top that's not visible and the top of the book on the bottom that's not visible.

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Last edited by ctbram; 18-05-2014 at 10:34 PM.

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# 6 18-05-2014 , 10:35 PM

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okay lets think about this. you have two boxes (books) on top of each other. The bottom face of the top book = 1 polygon, the top face of the bottom book = 1 polygon. 1+1 = 2.

Now you want to cut the top and bottom face of the bottom and top books (for what purpose I do not know.

But in the process you will create 4 triangles on the bottom and top face of the top and bottom books or eight new 3-sided polygons where you originally had only two 4-sided polygons and create bad geometry for the rest of the object unless you carry the cut edges all the way around the combined geometry. Fixing the geometry from teh whole new object and carrying the edges you cut all through the part will actually add a lot more then the 8 triangles on just the top and bottom faces in question.

Not to mention you also create a new problem for yourself when you go to texture these books because now they are combined and one is twisted and the bottom and top faces of the them are now combined in an odd way.

So what are you hoping to accomplish by doing this? You are not going to save polycon and you are only going to make texturing more difficult?

I mean it's not hard to combine them and I can show you how but in the end I see no real purpose in it other them clutter the geometry, add more polys, complicate texturing, and burn time better spent other other tasks.

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Last edited by ctbram; 18-05-2014 at 10:41 PM.

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# 7 18-05-2014 , 10:44 PM

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So are you saying I should leave them like that? I shouldn't overlap UVs (one of the rules they drilled into our heads at school) and if I leave them like that wouldn't it be kind of a big disadvantage that I will have a lot of uv space that is not visible and which will result in a lower res texture?

edit: ok I think I kinda realized what you're saying and I want consistency, I want the texture of the book on top to be the same res/detail as the one on the bottom.

Last edited by madwh; 18-05-2014 at 10:49 PM.

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# 8 18-05-2014 , 10:46 PM

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Well you would not really be overlapping them as they would be on separate geometry. You would have a separate set of uvs for each book. They would simply be on top of each other in your scene and the renderer would handle not drawing the sections that are on top of each other.

Imaging what would happen later if you wanted to add a third book or change the angle the two books are on top of each other or have a character pick one book up. You could not do the last one, and you'd have to remodel your combined book stack for every other change.

Better to model all the books as separate objects.

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Last edited by ctbram; 19-05-2014 at 05:57 AM.

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# 9 18-05-2014 , 10:49 PM

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Yep, I think I understand what you're saying, keep them separate and not worry about cutting out the faces that are not visible. I'll give it a try. Thanks.

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# 10 18-05-2014 , 10:51 PM

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yepper. This way you model one single book and as long as they are the same width and height you can texture as many different covers as you like and stack as many of them as you like and twist them all any way you like. The renderer will handle not drawing the overlapping bits.

When they teach not to overlap textures they mean on a single object or within a single texture map. Your books are two separate objects that will just happen to be on top of each other in a scene. You can either create independent texture maps for each, put all the textures on a single map and just scale and move each books uv's or even create unique maps for each book outside the 0-1 space (this is a bit more advanced).

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Last edited by ctbram; 19-05-2014 at 06:02 AM.

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# 11 18-05-2014 , 10:59 PM

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Still wouldn't mind figuring out how to snap/create a vertex where two edges intersect though.

edit: well my instructor just deletes the faces on the bottom of a mouse or keyboard or anything that's not visible. I guess it depends on what it's for: just a render, game, animation.

Last edited by madwh; 18-05-2014 at 11:04 PM.

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# 12 19-05-2014 , 01:21 AM

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Still wouldn't mind figuring out how to snap/create a vertex where two edges intersect though.

Originally Posted by madwh

The snap to curve will work and the two object don't have to be combined, what you are most likely doing wrong is when selecting the move tool you are probably selecting an axis instead of the center and free movement.

This is not the best way to get two objects on top of each other though, the easier way would be to move the top objects pivot point to the bottom (hit insert key select y axis on pivot and hold v key and MMB drag over bottom vertex of the top object and then hit insert key to complete or less accurate but quicker hold down d and manually position pivot) then in object mode select the top object and hold v key and MMB drag to a top vertex on the bottom object.

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Last edited by jsprogg; 19-05-2014 at 02:30 AM.

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# 13 20-05-2014 , 05:32 AM

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This is not the best way to get two objects on top of each other though, the easier way would be to move the top objects pivot point to the bottom (hit insert key select y axis on pivot and hold v key and MMB drag over bottom vertex of the top object and then hit insert key to complete or less accurate but quicker hold down d and manually position pivot) then in object mode select the top object and hold v key and MMB drag to a top vertex on the bottom object.

Originally Posted by jsprogg

That's exactly what I do for that part but I still can't snap a vertex to where two edges intersect and according to my instructor today it's not possible. No idea.

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# 14 20-05-2014 , 08:15 AM

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There is a work around for this use the split poly tool to create 1 vert that you slid to were the edges intersect then press enter, you know have a vert you can snap to and you can delete it after you have snapped................dave