3Ds Max UV Unwrapp Disappears after adding smoothing groups to the object !

VanessaCeline

So, in 3ds max, while uv ing i noticed that one face did not have a smoothing group. So I went to the Editable poly modifier, added a smoothing group to that face, and when I went back to the Unwrap UVW Modifier the uv editor was empty. This also happens if i collapse everything before and at the Unwrap UVW again. Does anyone know what is happening? ( Sorry if I chose the wrong forum category, it's my first time posting here. If anyone knows a better place where this could be posted don't hesitate telling me, thanks )

Eric Chadwick

I've moved this from General Discussion to Technical Talk.

UVW Unwrap modifier is very fragile. The edits you make depend highly on the vertices coming into it from down below.

If you do some UV edits, then switch to a lower modifier and change something, there's a high likelihood the Unwrap modifier will throw away all your edits.

Unwrap relies on the vertex numbering to edit the UVs. If you change those numbers, Unwrap will get confused.

Whenever you're done and want to exit the Unwrap modifier, right click on the modifier and choose Collapse To. The UV edits will then be "saved" into the modifier below it. 

Do whatever mesh edits you want, then add a new UVW Unwrap. You will see your UVs again, ready for editing.

I hope this helps you. 

VanessaCeline

@Eric Chadwick I have actually done that and, same thing, the unwrapp disappeared. I did not change anything with vertices or edges, just the smoothing groups. Do you think it would maybe work if I add an edit poly on top of the unwrap, and then another unwrap on top of that? Don't know if that's a bad idea or not. 

huffer

Do you have faces selected in Editable Poly before applying the Unwrap? Because the stack modifiers will apply to your selection only (if anything is selected) - so exit Face Mode, then apply the Unwrap and your existing UVs should be visible.

VanessaCeline

@huffer nope, made sure to select the mesh itself  

Eric Chadwick

It's a bad idea generally to stack modifiers which are vertex-order-dependent. It is way too easy to lose data, inadvertently. Whenever I need to do this, I am extremely careful, and I collapse as soon as possible. 

I suspect it is as huffer pointed out. Your selection has changed between edits.

Post screenshots of your stack, while you're editing the UVs, and while editing Smoothing, and when you're back in Unwrap again. 

Eric Chadwick

Which version of Max? 

VanessaCeline

@Eric Chadwick when I posted I was already doing the uv s since there was not much to redo in that specific case, so sadly I can not post a screenshot. I wanted to know how to avoid the problem in the future though. This is what I did: Edit Poly -> Assign Smoothing Groups -> Unwrap (with the mesh selected, not polygons or edges etc) -> Go back to the previous edit poly mmodifier fix some of the smoothing groups -> After I fixed the smoothing groups on about 2 faces I went to the unwrap uvw modifier above again, and everything dissapeared. I pressed undo a few times and redid the process to be sure that i have not selected any faces while doing the unwrapp, and i also once collapsed before setting the smoothing groups, and then added the unwrap uvw modifier once again. :-??    [ It is 3Ds Max 2019 ]

Eric Chadwick

I tried to replicate your issue here with Max 2018 and I wasn't able to. Changing the smoothing groups below an Unwrap works just fine for me.

Can you replicate it with just a Box primitive? Capture a simple video of the error, and share it. There's either something simple you're missing in your process, or else you've discovered a bug that needs to be fixed.

VanessaCeline

@Eric Chadwick 

Ok so, the problem does not happen on a cube. But there is one thing i noticed as a difference between my asset and the primitive. I exported my low poly from zbrush, so instead of editable poly at the bottom of the stack, I had "edit poly". The 2 of them seem to function in the same way though, or am I wrong? Could that be what caused the problem? 

Eric Chadwick

Screenshot?

Ghogiel

VanessaCeline said:

@Eric Chadwick 

Ok so, the problem does not happen on a cube. But there is one thing i noticed as a difference between my asset and the primitive. I exported my low poly from zbrush, so instead of editable poly at the bottom of the stack, I had "edit poly". The 2 of them seem to function in the same way though, or am I wrong? Could that be what caused the problem? 

There are minor differences between edit poly and editable poly. Off the top of my head you can add materials to face selections in editable poly, but edit poly if you drag a mat onto a face selection it'll just change the whole objects material.

I don't think you should be able to get an edit poly at the bottom of the stack.  If you import an obj from ZB it should be an editable mesh, which is different.