Edge extrude create unwanted "flat" polygons

[cynthia.desgagne]

I hope this problem is just me and that it's easy to fix, because it really gets annoying.

Here's my situation. I have a plane that I transform into Edit Poly, only one polygon. I select an edge, click extrude, 1cm height and 0 width. But instead of having 2 polygons, I have 4, the extras two being on the outside edge of the newly extruded polygon. These polygons aren't really visible, but they cause lots and lots of problems! I have a lot of extruding to do and I would love to specify the dimension of the new polygons, that's why I used Extrude instead of simply Shift-dragging.

Am I doing something wrong? Does anyone else has this problem?

At the moment, after each extrude, I select all my vertexes and do a weld with a very small threshold, that seems to eliminate those extra polygons, but it's annoying and counter-productive.

I'm using 3ds max 2012 64 bits, service pack 2 and I updated last week.

[sgiovanni]

hey if all you want to do is extrude the edge, just hold shift and then drag in the direction you want to translate   x, y ,or z, that shooooould work !

[cynthia.desgagne]

I know about Shift-dragging, but I need to use exact measurements at a perpendicular angle, so Extrude seems easier for me.

[cynthia.desgagne]

I attached a printscreen. I have the two extra polygons selected, not edges, polygons, created by extruding the edge.

[sgiovanni]

hmmm well  you have options,...     in my thinking I would  undo undo undo untill i was a tthe point right where i was going to extrude,.. then i would check to make sure there are no loose vertexes or edges in my geometry that could be causing the issue,.. then i woud click on the extrude options and make sure my settings are correct,..   ( make sure you will be making the correct amount of geometry,  some settings have it so when you extrude ther is extra geometry  i think it is the first or second setting in the cad menu, i dont have it open in front of me though =( so i cant say exactly)

if the problem still persisted, in order for me to not bring negative vibes to myself by cursing the gods,   i would just edit the geometry myself,   combine the vertices of the extra polys to dete them,... or you can just delete the polys all tegether and do the nessesary mending.   i know that can get annoying as ****,   but look at it as a  " for the time being just to get through this" type of thing,.. becuase the alternative is to be pissed,.. and you dont want to be pissed.  just get through it and keep in mind that its something you need to look into,. .you'll find the awnser eventually.    I always do so i dont see why you cant iether.

[cynthia.desgagne]

I have checked and re-checked my geometry, I start new objects and they all have the same issue. I counted the vertexes manually, no extra ones before doing the edge extrude either.
One thing you said is giving me trouble. You mentionned the cad menu? I'm in 3ds max, not autocad. If it's something else, I don't what this cad menu is. The onyl menu I have is by clicking on the little box next to Extrude, see the image I attached to this post.

[sgiovanni]

yeap thats the menu i was talking about .. i think it may be called the " caddy" or something like that ( as apposed to the cad, but im not really sure)   i dont know..  what the issue is though,...  your settings for the extrude look fine.. the second oval should be zero which it is... you could always just use the shift method to extrude it and eyeball it,.. in max, there is a general saying,     " if it looks good it is good"   i dont know what the project is that you are working on, but if it doesnt have to be exact then dont sweat it. 

if it does have to be exact you could always use tape measurer from the helper menu,.. although it may not be 100 percent it will be dam close.. just  type out the amount you want in the tape measurer and then match your extrude distance ( via shift move method)  with that one.

personally i think it may be eaiser to just eyeball it.

 to solve the issue for the future you may have to do a reinstall or a repair.  i have had to do that many times .  for varius reasons.  

[Steve_Curley]

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@cynthia.desgagne wrote:

I attached a printscreen. I have the two extra polygons selected, not edges, polygons, created by extruding the edge.

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No, you have 2 edges selected. They are Red in your image denoting that they are selected. Extruding an Edge creates a new polygon between the original edge and the extruded one. Polys MUST have edges on all sides therefore the 2 highlighted edges are normal, expected - and correct. Even if you Shift+Move an edge to extrude it you will still get those extra edges - you cannot have a new poly without them.

[cynthia.desgagne]

 I know the difference between an edge and a polygon, and what I have selected is two polygons sort of "collapsed" on themselves. They are triangles, they highlighted when I used the Select N-gons from the ribbon. That's the problem, I don't want/need them, I just want to extrude an edge and having one more polygon, but I always get 3.

[Steve_Curley]

Might have helped if you'd told us about that (n-gons, ribbon) earlier instead of leaving us guessing. Save the scene, zip it, attach it to a reply so we can actually look at it. If the underlying geometry is good then there's no reason for it to be creating "extra" polys. So either the geometry is not good, or possibly you have either corrupt config files, or a bad install. That can only be proved by trying the scene on another system, hence the need for the file.

[cynthia.desgagne]

I thought I was clear, sorry about that. I attach a scene.

I created a simple cylinder, transformed into Edit Poly, removed the top and bottom to have a few edges to play with, selected an edge, made Extrude with parameters 10 cm, and 0cm. Tada, two extra polygons!

I just finished reinstalling 3ds max (and re-updating and all), but it's still doing it.

[Steve_Curley]

I can see what's happening, but I don't know quite why. Depending on what I'm doing I pretty much always either Shift+Move an edge, or if I want all of them extruded, select them all and Shift + Scale them. Extrude I use on Polys, not Edges.
Either way, do your extrusions, select all the vertices and weld them. Should be easy enough to tell if the number of vertices now matches what you would expect. If you extruded all 8 edges (individually) you'd have 32 Vertices and 16 Polys.

[cynthia.desgagne]

I've been welding the vertices after each extrude for a while, and that gets annoying quite fast, as you can guess. No solution then? Would this be a bug in 3ds max, you think?

[Steve_Curley]

I don't think it's a bug - this is from the Help:-

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Extruding an edge moves it along a normal and creates new polygons that form the sides of the extrusion

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Just one of the things it's easy to miss if you don't use a specific tool in a specific way (which, as mentioned above, I don't). You could also call it a bug if used in the way described in the help and it didn't create those polys.

[cynthia.desgagne]

Well, thanks for the info. I'll try changing my methods or I'll bore my pain in silence, now that I know it's supposed to do that.

[PROH]

Hi. Just tested it in both 2012 & 2014, and in both versions extruding an edge in a Editable Poly does create extra polys. In fact I would be lucky if only one extra poly was created, often 2 or 3 extra polys was created. I tried several different settings, forms, workflows etc. with zero difference, when it comes to Editable Polys.

However, if you does the same on an Editable Mesh, then everything works as expected. No extra polys are created!

Maybe using Editable Mesh could be a workaround...

[luxxeon]

Yes, using the extrude command to extrude an edge will always create a manifold face, because it's always intended to be used with a width. Just convert to an editable mesh, do the extrusions you need, then convert back to poly.

However, i recall, there was a maxscript out there that did this very thing. Can't remember the name. Maybe "Extrude Open Edges" or something similar?

[cynthia.desgagne]

Thanks, I'll definetely try to find this "Extrude Open Edge". Or I'll try to write one myself (specifying an angle could be a nice thing too, and I do have years of programming behind me that could be put to good use).

[cynthia.desgagne]

Thanks, I'll try with a mesh.

[luxxeon]

Do a search over at scriptspot.com for extrude open edge.  I believe that's where I found it.  Here's the problem:  that script works to force the extrusion to non-manifold (single-sided) on edges when in editable poly mode.  However, you can't specify an angle.  You can, however, specify segments, which is quite useful.  So you can do one of two things; examine the script code and modify it yourself to include angles, or write the script author and ask him if he could quickly modify it to suit your needs.  It's free, and seems handy for this sort of thing, since you can specify exactly how long of an extrusion you need, or the number of segments.

Meanwhile, this is something useful to put into future feature additions for 3dsmax.  They should begin to migrate some of the Legacy Editable Mesh features like this over to Edit Poly anyway, if there are any left.  It's not that much of a pain to just switch between them, but the less steps the better. Most of the edit poly commands are geared toward manifold geometry manipulation, while edit mesh is for "old school" non-manifold manipulation.

Also, there may still be a technique that you can employ when doing the SHIFT+Drag technique to create new polygons from open edges, where you can control your segment length with snapping or something.  I'm sure there's a way.