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Flattening half-cylinder shape type

 
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MAF



Posts: 7
Joined: 21 May 2012

PostPosted: Fri Jul 20, 2012 3:59 am    Post subject: Flattening half-cylinder shape type Reply with quote

Hallo, as I often have to flat half-pipe style meshes I'd like to know if there's an option to tell UVLayout to start with some kind of UNROLL and then work with flattening. I'm asking this because using the flattening tecniques (shit-f / shift-b / space-f) after minutes the result is still not good.

I'm testing on the attached shape (original.jpg) and after 10 minutes the result is quite bad (flattening.jpg).

The mesh is not symmetrical if anyone asks Wink

Thank you for help!
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GeoffRiley



Posts: 72
Joined: 21 Feb 2007
Location: Cheshire, England

PostPosted: Fri Jul 20, 2012 4:46 pm    Post subject: Reply with quote

I'd suggest cutting the long strip into a number of shorter elements first; optimise each of those separately, and then when you're happy rejoin the elements together as desired.

With so many vertices in 'fingers' like that UVLayout is probably struggling to get rid of overlaps at the same time as flattening - the twin dilemma is giving it far more to do than if it were working on individual sections.

Hope that helps.

Kind regards,
Geoff
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headus
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Posts: 2902
Joined: 24 Mar 2005
Location: Perth, Australia

PostPosted: Fri Jul 20, 2012 5:50 pm    Post subject: Reply with quote

Exactly! Cut it up into smaller pieces, and weld those together.

You should also have a look at the UVLayout-Label-Pattern movie on this page ...

http://www.uvlayout.com/index.php?option=com_wrapper&Itemid=99

It shows you how to adjust the optimizing parameters to get the most accurate flattened shape possible.

Phil
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headus
Site Admin


Posts: 2902
Joined: 24 Mar 2005
Location: Perth, Australia

PostPosted: Fri Jul 20, 2012 7:40 pm    Post subject: Reply with quote

By the way, I was thinking about a better way to flatten out these sorts of trimmed shapes. As part of your modeling process, is it at all possible for you to export the untrimmed shape as well as the trimmed one we see above?

If you can, then I'm thinking I could write a new tool for UVLayout that would allow you to flatten out the simpler untrimmed form, and then that acts as guide for the quicker flattening of the trimmed shape. The simpler cylinder shape would flatten out much quicker (you wouldn't have to split it up into as many pieces), and then that flattening can be copied over to the more complicated trimmed shape.

Phil
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MAF



Posts: 7
Joined: 21 May 2012

PostPosted: Mon Jul 23, 2012 12:47 am    Post subject: Reply with quote

Hi, tahnk you for suggestions. I'm gonna try to split some. Wink
About exporting the untrimmed surface... I can say half of my works could be but half not. Expecially because usually I got 3D IGES files with many broken surfaces, open borders and things that need to be fixed. Fixing more than needed could take long time.
Maybe Phil, if you're up for coding a new tool, you can think about making an "unroll" type flattening based on a given radious that can be simply measured with the modeling software (I use Rhinoceros). Or maybe an axys based flattening.

I came to a good result by setting a cylindrical mapping in rhinoceros and then import and edit in UVLayout. See screen 1 and 2. At this point could be nice to flat on X axys and then use the standard flat for finishing.
It took an hour of flattening and some vertex moving by hand because of some vertex rolling on themselves in a vortex style... but the result was good!

I hope my explainations are not too smoky Wink
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