Extruding inwards - smooth mesh preview is jagged

# 1 11-08-2012 , 05:31 PM

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Extruding inwards - smooth mesh preview is jagged

Hello all,

I sincerely apologize for my terrible ability to be able to troubleshoot problems in Maya by searching for the error or disapproval of something but I am having a problem with how polygons look when they are extruded inwards to create some sort of depth. I am following an introductory tutorial for Maya by Digital Tutors and the instructor often likes to extrude inwards to give some additional detail.

Problem with this is that they appear to look jagged in the smooth mesh preview for what is supposed to somewhat resemble a circular shape. I have tried adding edge loops and bevels all around the object, as well as inside only certain edges within the object but have either ended up getting too much of a square shape or just smaller but numerous jagged lines. I believe it is because of the way Maya smooths the vertices and because the jagged points on the smooth mesh preview aren't actual vertices, it seems rather hard to straighten out.

I have no experience really with sub-d's so if this is a problem resolved using sub-d's, I suppose I will try using those to model out my shape.

Here are some screenshots of what I would eventually like to really straighten out without making the shape too squared off:

https://dl.dropbox.com/u/18672917/Hal...gine_block.png
https://dl.dropbox.com/u/18672917/Hal..._wireframe.png

https://dl.dropbox.com/u/18672917/Hal...Side_scoop.png
https://dl.dropbox.com/u/18672917/Hal..._wireframe.png
https://dl.dropbox.com/u/18672917/Hal...rame_front.png

I also just wanted to point out that I have tried to move those vertices closer together but the smooth mesh preview doesn't necessarily look any better than it did before... I understand that the texturing process can really kind of cover up some of these less-than-appealing areas by using some sort of dark or low-light look but I would still like these to look as sharp and smooth as possible. The instructor is clearly trying to get a point across in this intro course but I would still like to know how to be able to fix these extruded-in faces to look better.

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# 2 11-08-2012 , 06:30 PM

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The smooth mesh preview subdivides or "smoothes" the mesh twice by default which might not be enough to appear completely smooth if the original mesh is very low resolution. In the objects attributes (in its shape tab) there is a `smooth mesh` section where you can increase the subdivisions (and even display them too!)

- Genny
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# 3 11-08-2012 , 09:07 PM

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Wow GecT!! This is a huge game changer!! I was first curious to see if the render view would possibly change the jagged or unsmooth lines from the preview but it didn't do anything. Now changing the visible subdivisions really has made the polygon faces the way I intended them to see in the viewport. Thanks a bunch!
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*Self-Reference*

When I go into render view though, it's displaying everything at level 1 or the lowest level of subdivisions for some reason. Whether I check preview level for rendering or not, it doesn't seem to matter.

NoteSmooth Mesh Preview affects only the display of the polygon mesh in the scene view. If you render the mesh while Smooth Mesh Preview is turned on the mesh will appear in its original un-smoothed state in the final image.

If you want the mesh to appear smoothed in a rendering you can convert the smooth preview to a smoothed polygon mesh using Modify > Convert > Smooth Mesh Preview to Polygons or to a subdiv proxy using Proxy > Subdiv Proxy.
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So I just wanted one piece of that rear engine block's detailed area to be subdivided. I ended up selecting the faces for a portion of the back end and subdividing those using Convert Smooth Mesh Preview to Polygons. When I try to manually piece together the two pieces, I get this bad overlap and when I just try to combine the two, the high-res polygon piece now just seems to default to the lower-end polycount. Obviously I can subdivide the entire piece as I planned but that is a seriously high polycount for such a small portion of this jet.

Is there anyway I can combine the two objects without having both objects scale to a lower or higher polycount?

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# 4 11-08-2012 , 09:48 PM

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The Maya Software Renderer does not support the smooth preview mesh, however, Mental Ray does. Double check what render engine you're using because its not just a viewport thing (check the drop down menu at the top of the render view). I will say this, having a lot of geometry using smooth preview can start bogging down the viewport performance. It's mainly handy for reference and not a final smoothing solution.

Converting smooth mesh previews to polys can be problematic to work with even at the default smooth preview level of 2, the mesh density will skyrocket and its not the usual way of add geometry anyway. I don't know how your model looks now so I'm not getting a clear picture of your problem, it sounds like it can involve inserting edge loops, splits, merges and that may be complicating things and the instructor might not be heading in that direction. Save your work in regular phases, hopefully the instructor covers all this stuff. Also, post a screenshot user added image

- Genny
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# 5 12-08-2012 , 03:52 AM

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Here's the break in the rear engine block I was talking about when I tried to only subdivide and convert smooth mesh preview to polygons on the piece I wanted it to be sharpened up:

https://dl.dropbox.com/u/18672917/Ha...lock_split.png
https://dl.dropbox.com/u/18672917/Ha..._wireframe.png

As you can see, lots of unnecessary polygons user added image

but still trying to figure out how I can get the render view to look as smooth as the smooth mesh preview does when I subdivide it to lvl 4.

Also, I don't have Mentalray for some reason even though I've used it once or twice before somehow o__O

In the render window, it shows that I have Maya Software, Maya Hardware, Maya Hardware 2.0, and Maya Vector.

https://img.techpowerup.org/120811/Capture463.jpg

I'm sure I just need to change a setting somewhere.

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# 6 12-08-2012 , 04:45 AM

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Mmm, honestly that just looks like you have the mesh set to display the smooth preview subdivisions, uncheck it and tone down the subdiv levels. If you actually had smoothed it, it wouldn't look so low res in the maya software render.

And you don't have mental ray in the drop down because you probably don't have it loaded.

- Genny
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# 7 12-08-2012 , 07:23 PM

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Last time I used Mentalray to test some textures/materials, I recall now that I used some preloaded project file hehe user added image

so thanks for that tip.

Also, when you mean "actual smoothing", I assume that is when you go into Mesh > Smooth [] ? I smoothed the portion again and got a really high polycount and this time, it showed in the render view :]

Clearly I am a Maya newbie but is this what you essentially end up doing for the final render view for all polygonal objects? NURBS works in a similar fashion too I assume right?

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# 8 12-08-2012 , 08:52 PM

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Also, when you mean "actual smoothing", I assume that is when you go into Mesh > Smooth [] ? ...

Originally Posted by

Yep!

Clearly I am a Maya newbie but is this what you essentially end up doing for the final render view for all polygonal objects?

Originally Posted by

Yes, typically smoothing(there are a few ways) is done when the model is ready to be rendered, as smoothing/undoing can be clumsy and even a little risky.

NURBS works in a similar fashion too I assume right?

Originally Posted by

Yes and no. Yes, because they both can be setup to be subdivided at render time to desired levels. And no, because they are constructed differently there is no "smooth NURBS" operation you can just run to add resolution like you would a polygonal surface.

- Genny
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# 9 13-08-2012 , 02:56 AM

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While polygons seem much more flexible over NURBS so far, it seems that NURBS can quickly loft geometry together which is why I think I've seen many techniques for speed modeling utilize NURBS.

Thanks a lot Genny for your help. That feature for actual smoothing is very good to be aware of as I thought I was going to have to essentially remodel some parts of my jet just so I can have specific areas sharpened up (pretty sure these are what sub-div geometry is good for).

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Extruding inwards - smooth mesh preview is jagged

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