Symmetry, and Extruding

[EricUjfalussy]

Hello fellow Maya Users; 

I feel like this has been an issue for a few years now, and I don't think I am the only one who runs into it; but I figured I'd post here to see if theres support. This is an issue that happens in most versions of Maya; I think even dates back to probably 2020 or earlier? Maybe some of my other old heads can confirm. 

Turn on Symmetry (World X in my Case)
Select Faces
Hold Shift, then use the Translate to Extrude

What will happen is the entire model will end up moving, and not actually extruding and moving just those selected faces. It's incredibly annoying and really kills the intuitive function of the Shift Key. Is there any way to solve this? Obviously Autodesk isn't going to prioritize a small issue like this but I would love to hear input. 

[Christoph_Schaedl]

Think thats only happening if the object is in a group and the history is not frozen.

[brentmc · Accepted solution]

Hi,

We are aware of this issue and I believe it only occurs when using symmetry and deleting history should resolve it. (if I remember correctly)

Shift-extrude is not the best way to create clean meshes since it effectively creates a zero-length extrude and then translates the newly extruded  faces.

This has a bunch of problems:

• the zero length extrude can wreak havok with normals on the side of the extrude
• you can't go in and edit the extrude node to add divisions or anything like that without causing your geometry to explode. (because that will change the topology and change which faces are translated)
• you can accidentally create zero length extrudes while trying to shift-select faces. You end up with a bunch of zero-area faces on the edge of the extrude and two faces sitting right on top of each other. Needles to say this bad topology will likely lead to issues later on.

I know you don't want to hear this but you would be better off sticking with Ctrl+E for extrude and turning off Shift-extrude in the preferences.

[EricUjfalussy]

Bit of a bummer! Totally understand why it's not the best, but the function of it is great; sad that it causes so many issues. If I do a shift extrude I usually end up adding edge loops in after if I need to. Back CTRL+E it is for now.

[aparnavats]

for right and left both portion will be same ,from  center part of the  car model  you have to select faces all and delete half car and go to edit menu bar and go duplicate special  option choose click instance and scale axis's x,y,z one axiewill be minus . second point select faces from right click  and go to  edit mesh  extrude ctrl e 

[EricUjfalussy]

Yes, this is the way I work for most of the time. For instance (haha nice pun)... A lot of this car is built using instances. However; this symmetry issue has been an issue for a while. Probably no point in trying to change the way Maya works now though lol.

[MariSalia50mmm]

Why should artists be expected to know or care what a “zero-length extrude” is, or any other under-the-hood implementation detail?

In 3ds Max, Blender, etc., interactive extrude simply works. I don’t know what it does internally and I don’t want to know. That’s the baseline expectation for professional tools.

This software costs an arm and a leg. If I buy an expensive car and something fails, the solution isn’t a lecture on the engine design, it’s fixing the problem.

As a modeler, I perform thousands of extrude and inset operations per session. Suggesting that repeatedly invoking hotkeys is a better alternative than direct interactive dragging is simply not realistic. When this feature works, no one recommends avoiding it - this advice only exists to work around a broken implementation, not because the workflow itself is "bad".

So the real question is: if other 3D applications can implement a robust interactive extrude, why can’t Maya? 

[nana_1961]

Maya is just a bad program for modeling. It’s fundamentally broken, and there’s clearly no intent to fix it. Asking for resolutions is a waste of time when they just pile buggy new features on top of old ones to check a box. Most of these tools never worked and likely never will. Take the conflict between symmetry and shift-extrude: they won't fix it, preferring to label it a "bad workflow" and move on—even though they’re the ones who created it.

To make matters worse, they recently tacked on "Smart Extrude," another "fancy" feature that creates nothing but errors. The response will likely be the same: "bad workflow," zero-length extrudes, and so on. Save yourself the frustration and switch to a better program. If they haven't fixed a simple extrude since 2018, it speaks volumes.