Maya, nonmanifold geometry issues. Solution?

Axcel · Mar 2019

HI,
How to ignore errors like: error: line 0: cannot reduce polygonal object with nonmanifold geometry...

Many tools (scripts) doesnt work in maya, cuz of nonmanifold geo.

No such problems with 3ds max, unreal or whatever. They just work with any geo. Unfortunately i have to work on maya. How to go around its limitaitons? Clean up didnt help at all.

For proxy out enviro, i dont need perfect geo to work with, but i need to have flexibility in tools such as mesh reduce.

oglu · Mar 2019

cleanup should find the issue.
could you show us what it does find?

poopipe · Mar 2019

nothing works properly with non-manifold geometry, max just doesn't let you create it

cleanup will find usually find your problems - it won't necessarily fix them properly - usually telling cleanup to select and then manually deleting the problem components will get you there.

Alternatively, one thing that can help is exporting to FBX as that'll shatter any verts contributing to non-manifold geometry - you'll end up with a load of unwelded verts but at least the mesh will be valid.

if the geometry is utterly shit you should probably just rebuild it though

Sage · Mar 2019

The big issue with Maya is that you can't delete verts or edges like say in Max or Blender. It only lets you delete in face mode. It makes cleaning the non manifold geo a pain. Maya seems to create bad geo just by selecting it. It seems to do it randomly. You make a boolean for example you get non manifold geo sometimes. Sometimes it works fine, same with quad draw... If you use Maya you just have to spend hours fixing bad geo. To clean bad edges I have to convert the selection to faces then delete.

poopipe · Mar 2019

I see this sort of complaint fairly often.

While Maya is unforgiving, and frankly a fucking awful modeling tool it is entirely possible to manipulate geometry without generating shite - I do it all the time, as do many others.

If you find yourself having to clean up your own work all the time you need to reassess the way you build things.

Benjammin · Mar 2019

A trick I've found to work fairly often is to use mesh cleanup to identify problem vertices. Detach/split those vertices, then weld them again.

Alex_J · Mar 2019

Sage said:

The big issue with Maya is that you can't....

This isn't true. Or, at least it doesn't need to be. I have been using Maya for about 1.5 years but after about 6 months of use I was no longer having to work like this. Rarely ever do I touch the cleanup operation tool. If I do have bad geo it is always immediately clear how it was created, and cleanup takes a few seconds... I guarantee you I'm not a particularly smart person. Of course if you learn some other program first coming to a new one will be difficult. I'll admit the one time I tried out max I lost my patience pretty quick. Compared to what I'm used to with maya, max seems very obscure and overly technical. But that's just a noobies first impression, so it's not worth squat.

I am not sure what you mean about not being able to delete vertices. You can delete vertices. If regular delete does not work becuase its non-manifold, you use backspace delete. I think thats' the hotkey anyway, I never need use it. But backspace delete removes an edge and all dependent vertices, or vice versa.

Axcel · Mar 2019

Thank you poopipe ans sage for valueable insight!

Not exactly my geo. To proxy out stuff quickly, we tend to use free models. Fine with max... not with maya i see.

Do you apply cleanup tool in object mode with selected object, or with selected particular component?
btw: Ctrl + del, deleted edges with vertices.

Sage · Mar 2019

Delete doesn't work like in other programs, like I said. I expect a hole in the mesh when I delete a vert, face or edge. It does not happen in Maya. So what I said is very true. To clarify, when you delete a face in Max, Maya, and Blender you get a hole in the mesh. When you delete an edge or vert in Max and Blender you get a hole in the mesh. When you delete a vert with backspace or the del button nothing happens. Again what I said is very true. When you do the same with an edge the edge is removed but the verts and face remain. Ctrl + backspace gets rid of the edge and verts but the face remains.

Dissolving an edge or vert is what happens when your press ctrl + delete or ctrl backspace. That doesn't always work. Sometimes Maya makes two edges on top of each other. When it fails it seems totally random as well. What else doesn't work sometimes, bridge, weld, target weld. It's awesome to model in this program.

I take great pride in making clean geometry but I spend hours at times fighting the program because it just want to do weirdness. Maybe the student version of Maya comes with Grimlins, but I doubt it. I usually just use mesh cleanup if needed. I get the error when unwrapping at times.

At any rate I am not bashing Maya. I really have no interest. Max and Blender have their own issues. I was just sharing some workarounds I have developed to deal with how Maya at times makes cleaning up geometry a total hassle with Axcel.

Autodesk acquired Alias back in 2005. Modeling in Maya felt like a 20 year old modeling software back in 2017, after using Blender. Now that 2018 has the smart duplicate options I enjoy modeling in it a lot more, except when I get geometry issues. I just feel it shouldn't be so flaky.

@Axcel I apply cleanup to the object in object mode. In the remove geometry I turn on lamina faces and nonmanifold geometry.

Alex_J · Mar 2019

i dunno, those things you mention never give me issues. It's probably a matter of expectations. You have experience with many programs and thus expect things to work a certain way. And probably your typical workflow isn't in perfect compliance with the way Maya works. But I only know maya, so the way I've developed of working just doesn't develop any issues with common tools like bridge, target weld, etc. I used to, so I can imagine what you might be doing to cause these issues, which is why I suspect it's more often user error case. Not implying you are a dummy or anything, just that you have workflow habits better suited to different programs.

Like, to me, delete a vertex causing it to chamfer and make a hole seems counter-intuitive. Like adding extra steps I may not have wanted. Just doesn't make sense. My normal workflows don't usually have me deleting vertices at all really.

Anyway, not trying to drag out some silly argument, but the thing is when more experienced people say things like "argh, maya sucks!" and some newbie reads that, then the next time they have some difficulty in maya they're gonna quit and waste time trying to learn some new program when really they don't know any better. I understand there is more nuance behind your decision making but when it gets distilled down to, "this program sucks" it just kind of perpetuates this bad attitude among lesser experienced folks.

poopipe · Mar 2019

Axcel said:

Thank you poopipe ans sage for valueable insight!

Not exactly my geo. To proxy out stuff quickly, we tend to use free models. Fine with max... not with maya i see.

Do you apply cleanup tool in object mode with selected object, or with selected particular component?
btw: Ctrl + del, deleted edges with vertices.

That's a workflow I can identify with, and one that maya doesn't take naturally to.

Cleanup only works in object mode.
It's best to be targeted with your selected options in the cleanup dialog when dealing with shit meshes.

As I said, tell it to select rather than cleanup, pick a couple of related things to search for at a time, delete/weld them as appropriate and clear history between each step. Clearing history is important because old shape node information will interfere with results

The most insidious errors are unwelded coincident edges that share the same vertices. I'm not sure cleanup will detect those but you can usually spot them by highlighting border edges

Axcel · Mar 2019

More useful info. Thanks poopipe!

Maya, nonmanifold geometry issues. Solution?

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