Network Curve selection

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 From:  mash (MASH3D)
4453.1 
Hi, minor question when selecting network curves does the order of selection matter?
thanks
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 From:  Michael Gibson
4453.2 In reply to 4453.1 
Hi mash - no the selection order doesn't make any difference - the Network command will analyze how the curves touch each other and form the proper ordering from that information.

But you do need to have a structure that will work with Network - it needs to be able to be unwrapped to a 2D grid pattern.

See this recent post for several links to examples of how you need to have the input curves arranged:
http://moi3d.com/forum/index.php?webtag=MOI&msg=4448.4

- Michael
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 From:  mash (MASH3D)
4453.3 In reply to 4453.2 
Thanks for the info.
I used to do a lot of spline cage modeling and wasn't sure if the limitations of that method applied.
You had to select the splines in counter clockwise order, same number of points etc, etc.
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 From:  Michael Gibson
4453.4 In reply to 4453.3 
Hi mash, there are some other kinds of things where the selection order can matter, the main one I can remember at the moment is Loft.

For loft if you select each curve by clicking on it, it does make a surface through them in the order that you selected them. If you do something like window select a group of them then it tries to automatically sort them, but that can get confused if you have something like 3D swooping profile curves all at various angles to each other.

Network is a bit different because it takes 2 sets of curves that cross over each other, so it's able to use the crossing information to figure out how things relate to one another.

Loft is a one-directional thing and it doesn't have as much structure to the inputs to give it the ordering in all cases. But for simple cases like when the curves are all on parallel planes the automatic sorting in loft can figure out how to arrange stuff like that.

- Michael
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 From:  mash (MASH3D)
4453.5 In reply to 4453.4 
One thing 'm trying to keep in mind is polygon flow because I'm going to be exporting the model out.
Is there any way to preview the way the polygons will lay with out having to do an export first?
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 From:  Michael Gibson
4453.6 In reply to 4453.5 
Hi mash,

> Is there any way to preview the way the polygons will
> lay with out having to do an export first?

You have to do an export to see how it's going to mesh, but you can set up a keyboard shortcut that will do an export to a dummy file name and then just cancel instead of actually writing the file.

That's pretty convenient because it avoids having the file dialog come up at all.

To do that go to Options > Shortcut key, and add in a new entry.

On the left-hand "Key" column put in the key that you want to trigger the shortcut. If you do this a lot put in the space bar by typing: Space into that column.

Then on the right-hand "Command" side put in the following:
SaveAs c:\test.obj


Then with that in place when you hit the space bar it will go through the export process but use c:\test.obj as the filename, so it skips the "ask for a filename" step and goes directly into the mesh previewing. Then when you're done looking hit escape or push cancel to bail out, it won't write any file if you cancel at that point.

- Michael
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 From:  Michael Gibson
4453.7 In reply to 4453.5 
But also you mention being worried about polygon flow - what is it that you are planning on doing with the mesh that you are specifically concerned about that?

If you need a particular kind of polygon flow because you plan on doing sub-d smoothing, you really aren't going to get that kind of a result from MoI's export. MoI's export is more oriented towards making an efficient polygon count with a lightweight wireframe using n-gons. That's a very different kind of mesh structure than a sub-d friendly one which requires a lot more tiling of large areas into numerous quads instead of using something like one big n-gon for a large flat face.

See these previous forum posts for some additional explanation:

http://moi3d.com/forum/index.php?webtag=MOI&msg=3628.132
http://moi3d.com/forum/index.php?webtag=MOI&msg=4096.18
http://moi3d.com/forum/index.php?webtag=MOI&msg=3488.3
http://moi3d.com/forum/index.php?webtag=MOI&msg=3196.11

http://moi3d.com/forum/index.php?webtag=MOI&msg=1536.30

- Michael
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 From:  mash (MASH3D)
4453.8 In reply to 4453.7 
I have take some IGS files and convert them polygon models, proably sub-d at that.
I know MOI won't give me a perfect Mesh for that sort of thing. But if I can do anything to reduce my work on the polygon side of the pipeline it helps. Worse case I can do a retopo in 3d coat.

I'm also starting to have to reproduce items, cars etc, that were clearly made in a nurbs package.
But having to build them with sub division modelling is a pain.
Using MOI just to produce a fast low res model can be a big help on the poly modeling side.

EDITED: 29 Aug 2011 by MASH3D

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 From:  Michael Gibson
4453.9 In reply to 4453.8 
Hi mash - yeah basically MoI (with the n-gon option active) builds a mesh that resembles and follows the same topology as the NURBS object - things like one n-gon face for one trimmed planar NURBS surface, etc...

That's a nice clean structure in a lot of ways, like not a lot of extra wires but it's just a generally different kind of structure than what you'll need for sub-d except in particular special cases like with untrimmed surfaces.

But that's great that you've got 3d-coat and can use that for retopo if needed.

I just wanted to clarify that - it's kind of a frequent thing that people see Moi's structured n-gon output and seem to automatically jump to the conclusion that a clean looking wireframe and organized looking topology equates to sub-d friendly topology, when that's not necessarily the case.


If you are looking to produce a rendering of your models, you can just render MoI's output directly - it includes vertex normals with the output which helps things look smooth in the rendering without having to apply any sub-d smoothing on it at all.

- Michael
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