Shell Issue

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 From:  kevjon
6280.1 
I'm using the latest beta but can't seem to give this canopy thickness with shell, it keeps failing, any thoughts as to why ?

I'm tyring to give it a thickness of 0.012
~Kevin~
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 From:  Michael Gibson
6280.2 In reply to 6280.1 
Hi Kevin, as far as shelling goes that's a quite complex thing to try and shell.

You've got some sharp corner areas - that becomes difficult for surface shelling because the offsets of the pieces being shelled need to be extended and it's actually the extensions that then intersect and the geometry library that MoI uses is not very good in handling this.

So usually for thickening an open surface you'd want to be working with just one surface or some pretty simple object in order for it to have much chance of working.

Other CAD programs based on the ACIS or Parasolid geometry libraries are much more sophisticated at shelling operations than MoI's geometry library, so you if you have ViaCAD or a different CAD program you might try exporting it there.

But you may have difficulty shelling it in any package, things like this area here where you've got a combination of tightly bent shapes, maybe some ripples and bumpy surfaces and some partially creased spots all in a tight area are pretty difficult things to handle:




- Michael

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 From:  Michael Gibson
6280.3 In reply to 6280.1 
One thing that you can do to kind of get started is to run Edit > Separate on your object to break it into individual surfaces, then use Offset to offset all the surfaces. That will get you some chunks of stuff to work with - the offset surfaces will meet up ok in places where surfaces were touching each other smoothly but in areas where there were creases there will be gaps between the offset surfaces that you'll have to fill in. And also in areas that were tightly bent it's possible for the offsets to be bunched up and self intersecting.

- Michael
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 From:  kevjon
6280.4 
I suspected that tight area might be the problem. Its probably trying to self intersect in that area.

I also tried to shell it in viacad and it came out with the cryptic message "could not offset surface as requested:Thick Solid_331", so your guess is spot on.

Thanks for the suggestion about offsetting surfaces and breaking it down into more smaller chunks. Its a little more work but should give me the desired results. Will do it that way.
~Kevin~
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 From:  blowlamp
6280.5 
I did what Michael mentioned in his second reply and Separated the surfaces, I then Shelled them (Direction = Flip) and finally Boolean Unioned them.

There are a couple of problems at the front that might be editable, but overall it's not too bad from what I can see.


Martin.
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 From:  kevjon
6280.6 In reply to 6280.5 
Thanks blowlamp for the tip. That will make it quicker and easier. I never considered that option so glad you suggested it.

In this case I don't need perfect surfaces on the interior so a couple of bad joins here and there won't matter.
~Kevin~
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