Hi Max,

> importObj supports n-gons :)

Oops, I see now I didn't read it close enough - I saw the if (edges.length<5) part and I thought that was the main thing, but now I see that's only a backup path for if the polygon was not planar enough for planarsrf to construct a surface through it. Sorry!

I guess if the n-gon is non-planar then that will be an issue though?

- Michael

Hi Michael,
>>I guess if the n-gon is non-planar then that will be an issue though?
Yes, exactly.

Just found a stange obj export bug. When I export "O" letter using n-gon mode, MOI creates four strange polygons instead of normal quads.

f 83/83/83 101/101/101 85/85/85 86/86/86 102/102/102 84/84/84
...
f 97/97/97 103/103/103 98/98/98 99/99/99 104/104/104 100/100/100
...
f 105/105/105 137/137/137 106/106/106 107/107/107 138/138/138 108/108/108
...
f 119/119/119 139/139/139 121/121/121 122/122/122 140/140/140 120/120/120

So importObj can't properly import it.

Hi Max - it's not unusual to get n-gons possibly with some of their points nearby each other in various juncture areas. There it looks like it's the cut through the middle to deal with the interior hole in the top surface that is probably introducing the points you don't want. That's just part of how the mesher works... OBJ format does not have the concept of a polygon with a hole in it, so any n-gons that would have internal holes within a single n-gon like the top face there will get divided which can easily introduce additional boundary points.

- Michael

Hi!
I'm back (for a while ;)

This weekend I wrote a new beta of subdiv script. Yes :) I finally did it! :)
This version is very unstable, but it works much better with extraordinary vertices. C1 continuous on extraordinary vertices, and C2 on ordinary vertices.
It doesn't support triangles in hq mode yet, so you need to use quads only.
Of course some surface issues may occurs. I think there may be some bugs.
Also I plan to write an optimization block, which can stitch separated ordinary quads to one surface.

Extraordinary script! ;)

Hi Max,

Sounds incredible!

Just so I understand how this works...

Can I import an OBJ non sub-divided created in a program light Lightwave, and this script will convert it to NURBS? If so-- WOW!

Hi Max,

It's late here, so I'll torture your script tomorrow.
I have to say that the results on the provided examples are really amazing.
It's way beyond my expectation, it looks much better on hi-valence point than some commercial plugins Oo

Hi chippwalters,

The .obj import is here :

http://moi3d.com/forum/index.php?webtag=MOI&msg=6674.68
http://moi3d.com/forum/get_attachment.php?webtag=MOI&hash=8e7570bc59ea9e111727dcc1a5a5a3dc&filename=importObj.zip

Hi chippwalters

This script is more useful for subdivision surface modeling.


Yes, it can process OBJs, but it will produce a huge amount of surfaces. I need to find the way to build more complex surfaces.
But anyway, it works! :)

Super cool stuff Max!

- Michael

Hi Max, some really good looking results in high quality mode!

Only with some more detailed examination with reflective zebra stripes can some G2 discontinuities be seen.

Have you thought any about non-uniform refinement, like with extra density clustered more tightly just around extraordinary vertices rather than uniform refinement?

- Michael

Hi Michael, I noticed some artifacts on surfaces in some cases, but I think there is a bugs in the code. Yesterday it was worse than now. :) I've already found and eliminated several bugs, but I'm sure that some bugs I missed.
I implemented this algorithm:
http://www.cise.ufl.edu/research/SurfLab/papers/10fan_sbs.pdf
I think it really can produce perfect surfaces

Yes, I thought about non-uniform refinement, and used it in previous version of this script. But I wasn't satisfied with results. So I will play for a while with this algorithm, but if I'll still have problems with it - I'll bring non-uniform surfaces back.
Here is example of non-uniform surfaces:
http://moi3d.com/forum/index.php?webtag=MOI&msg=7038.12

Hi Max,

I was looking forward to see your update!!
Your examples look great, but i'm unable to replicate them.

It seems that the script only works on a primitive cube or extruded rectangle for me.?
Any thing drawn with a polygon line or booleaned solid either gives the error "unsupported polygon type! (2)" or the object just disappears.

Hi Glenn
This script doesn't support n-gons. Use triangles and quads.

I know about object disappearing bug. I'll take care of it.

Subdiv beta 4 :)

Fixed some geometry bugs
Improved mesh load speed (about 10x)
Added support of polar triangles


Don't use any other types of triangles


Added handy feature: switch mode
If you use hotkey to run this script, put the same key combination as command parameter
Example: Key: Z Command: _Subdiv_beta4 Z
After that you can switch script on and off with Z key.

Hi Max,

Thanks a lot for the update.

I have some really hard time to import anything a little bit complex
Here's for example what I get :

1290 Geometry error, 1290 recovered.



I'm not sure if it's something wrong with the .obj loader I use (the one coming from http://moi3d.com/forum/index.php?webtag=MOI&msg=6674.68 ) and if there is
anything you can 'do' to improve the loader. Looks like the loader have some trouble to deal with extreme non planar quads.

I checked this model. There are many twisted non-planar quads in the obj. I'll think how to improve my importObj script for using it with such complex models.
The scripts works well with other complex models with non-planar quads .
for example:
http://www.craftsmanspace.com/free-3d-models/skull-3d-model.html
http://www.craftsmanspace.com/free-3d-models/piggy-bank-3d-model.html
http://www.craftsmanspace.com/free-3d-models/african-elephant-3d-model.html

Hi Max,
_Subdiv_beta4 don't work for me on V3 MACSOX
I put the command _Subdiv_beta4 with Tab key but the panel Subdivision don't stay visible.
i've tested with skull and elephant
but in Moi if I put a solid Box and run the command _Subdiv_beta4, it's OK.
I think it's a matter of Mac and Memory.
Thanks

Hi Max,

First thank you a lot for all the effort you did on this polygonal converter.
I have no idea of the complexity to write something like that, but I just want to point a general 'smoothing' problem with the method you are using. (and I'm not talking about surface continuity)

In the image :



A ) Max Sub-d : Low Quality
B ) Max Sub-d : High Quality
C ) Npower SubD-Nurbs.

My concern here is the wobble effect from the version B (Max Sub-d : High Quality).
This wobble effect is also visible on object silhouette. I know that I shouldn't compare your script to
a commercial 500$ product, but I'm wondering if it's something that might be improve in the future ?

In other words, while you manage to keep continuity between patches, it seems the side effect is an overall shape/silhouette deformation. It's something very obvious for polygonal surface subdivision people, used to see very smooth surface transition and ultra smooth overall silhouette. (catmull-clark)

Thanks.

Hi PaQ,

Thank you for this valuable information. I have some ideas how to improve quality.