Maya smooth preview artifact in mesh

shxsy

I've been trying to do some more hi-poly stuff in maya 2013. I've got this pretty simple piece set up and I can't figure out whats going on with the smooth preview. I've put in control loops around the circles and have creases the outer edges(set to 10). The problem is that when I preview, the mesh distorts at the verts, like they're pinching. I've tried a million things. I've gone through all of the options in the display>polygon menu, played around with beveling. redone some of the edgeflow, tried some different edge softening/hardening, but nothing seems to work to get that edge clean. Looks great where there are control loops, but the creasing looks like garbage. Any thoughts? Is creasing the wrong way to go?

antweiler

Mayas smooth preview adds two divisions by default. Have you checked how it looks if you increase the divisions? (in the meshs shape node: smooth mesh>Sudiv Levels>Preview Division Levels)
You can also preview the smooth preview divisions, then you can see better, what happens.

Bartalon

The problem is you have those triangle points landing on a corner. When a triangle subdivides the edge flow goes in every which direction compared to quads that are very neatly directed in perpendicular directions.

You will want to reinforce your topology with a ring of quads in order to get rid of that issue. Ideally you should support all your corners with quad rings. It helps maintain the shape as well as give you more freedom to make shapes and tie off troublesome edge loops on the inside of these rings.

aFungusAmongUs

Its because you have those poles on the edge, Maya smooths with a subdivision and those poles make it want to interpolate that as a curved edge and effs your normals regardless of how much you harden it. Add a control loop to get the poles off the edge, that should get the artifacts fixed. Hard edges need that protective border of clean edge flow in order to hold their shape properly.

heres a quick brick to show the difference it makes
https://www.dropbox.com/s/mfjjbl1qxu1rqd8/hardedges%26poles.obj?dl=0

Yonderboy

yeah, i think this is one of the problem with using the crease tool (as I do). Not having to add those supporting loops around the edges to harden things up means you end up with issues like this.

shxsy

Ahhhh..... So it seems like creasing is almost pointless? As a rule of thumb, is creasing to be avoided if the intention is to bake down the hi-poly asset? Like... creasing gives that nice 'machined part' look to your assets, but isn't necessarily great for baking out maps? I'm I correct in that assumption? What do people think?

Bartalon

Personally I've never tried baking a model that exclusively uses creases. For me it just comes down to it looking terrible in the viewport. It's really difficult to gauge how smooth a corner is with that ugly gradient that is present. I guess it's trying to simulate a curved surface visually but it's still a super tight edge. You might be better off with standard bevels and support loops.

Maybe look into the following sequence of tools to help speed up your support looping:
Modify > Convert > Polygon Edges to Curve
Curves > Offset > Offset Curve
Surfaces > Loft

Not to say creasing is worthless. It can be very useful when utilizing software like ZBrush where it does a better job at maintaining creased corners after subdividing. But I've found very few uses for creasing when creating high poly models within Maya.

shxsy

That seems like it could work. The lofting took a bit of futzing with to get it work how I wanted it too and required a bit of cleanup, but the then result was pretty good. I can see it being really useful for edges that are more curved/organic looking. Thanks for the tip.

Bartalon

Loft should be able to match your curves 1:1 with no cleanup, just gotta choose the right settings.

throttlekitty

shxsy wrote: »

Ahhhh..... So it seems like creasing is almost pointless? As a rule of thumb, is creasing to be avoided if the intention is to bake down the hi-poly asset? Like... creasing gives that nice 'machined part' look to your assets, but isn't necessarily great for baking out maps? I'm I correct in that assumption? What do people think?

I still haven't come to grips with creasing either. I like it, but I tend to run into lots of little cases where I also need standard support loops to hold a shape. And then you make some edits and all the creasing gets distributed around to the whole model. And that's a difficult way to work.

So I just use it for smaller/simpler pieces that I can easily predict the outcome rather than say, a whole mech.


edit: back to your original question: Like the others said, it's your topology. Don't try to save polys in that way, you'll need to continue the loops down the walls. You're just creating new flows giving the top "weight" to pull those poles in.

a3D

Crease has its uses, but it cannot just replace standard subdivision modeling all the time.

Personally I tend to use it on support loops, instead of using double support loops. Keeps the mesh lighter and produces equally good results.