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Blender: How to create meshes without tons of n-manifolds [message #2238] Mon, 15 December 2008 09:06 UTC Go to next message
avatar Mick Lang  is currently offline Mick Lang
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Hey everyone,

I've got a dilemma and every noob2pro/book or guide I've found doesn't answer the question on how to create extruded models without non-manifolds.

I create 'bodies' of a mesh that are simply one-sided. When I extrude them (by region), I get loads of these non-manifold polygons that take hours to correct. Is there a better way to create objects that have double-walls?

Thanks for your help and happy holidays!

Mick
Re: Blender: How to create meshes without tons of n-manifolds [message #2240 is a reply to message #2238 ] Mon, 15 December 2008 14:22 UTC Go to previous messageGo to next message
avatar bartv  is currently offline bartv
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Hi Mick,

that's not easy to answer without seeing your models. Could you post the model before and after extrusion? I'll then take a look at it for you.

Cheers,

Bart


Community Manager Europe | Shapeways
Re: Blender: How to create meshes without tons of n-manifolds [message #2249 is a reply to message #2240 ] Tue, 16 December 2008 18:22 UTC Go to previous messageGo to next message
avatar Mick Lang  is currently offline Mick Lang
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Here's the .blend after extrusion.

Thanks,

Mick

[Updated on: Tue, 16 December 2008 18:27 UTC]

Re: Blender: How to create meshes without tons of n-manifolds [message #2250 is a reply to message #2249 ] Tue, 16 December 2008 18:25 UTC Go to previous messageGo to next message
avatar Mick Lang  is currently offline Mick Lang
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Hi Bart,

Attached are the two blender files. The first, with 'no_extrusion' as the file name, has just the shell of the mesh without being extruded. It only has one side.

After I select the polys that I want extruded, I performed an 'individual face' extrude and get (as predicted) loads of non-manifolds.

Is there a recommended way of extruding or adding a second face onto a mesh so that I can have a hollowed object in Blender?

Thanks for your time-- I really appreciate it.

Mick

Re: Blender: How to create meshes without tons of n-manifolds [message #2251 is a reply to message #2238 ] Tue, 16 December 2008 19:14 UTC Go to previous messageGo to next message
avatar frigi  is currently offline frigi
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Don't use "individual faces" because that does exactly what it says, it extrudes individual faces. You really don't want that.

What you should do instead is use "region" and then scale it along the normals with alt+s or even better: Just use the solidify script. (mesh -> scripts -> soldify selection) Most of the times you get better results with that.
Re: Blender: How to create meshes without tons of n-manifolds [message #2252 is a reply to message #2251 ] Tue, 16 December 2008 19:18 UTC Go to previous messageGo to next message
avatar Mick Lang  is currently offline Mick Lang
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Thanks Joris!

I currently don't have that script loaded, but I'll go get it now.

Thanks for your great help!

Mick
Re: Blender: How to create meshes without tons of n-manifolds [message #2264 is a reply to message #2238 ] Wed, 17 December 2008 19:49 UTC Go to previous messageGo to next message
avatar frigi  is currently offline frigi
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I'm not exactly Joris but I'm glad I could be of help anyhow. Wink

You don't need to download that script btw. it's built in right in Blender. (just follow the instructions I already gave you)

Yours,
Fabian
Re: Blender: How to create meshes without tons of n-manifolds [message #2265 is a reply to message #2264 ] Wed, 17 December 2008 21:36 UTC Go to previous messageGo to next message
avatar Mick Lang  is currently offline Mick Lang
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I'm sorry Fabian,

Dumb-ass me for some reason thought it was Joris that supplied that bit of help.

Thanks a million anyways. My 2.48 version didn't have any scripts (or it was loaded wrong. Either way I downloaded the scripts (and correct version of Python) so I should be on my way.

Thanks again and happy holidays!

Mick
Re: Blender: How to create meshes without tons of n-manifolds [message #3320 is a reply to message #2265 ] Wed, 11 March 2009 16:51 UTC Go to previous messageGo to next message
avatar Joseph O' Connor  is currently offline Joseph O' Connor
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Hi, I would appreciate some help.
I use Ashlar Vellum Cobalt to creat my 3D models. So far so good as I have never had a problem with an STL file before.
I upload it to shapewaysand am told that it contains non- manifold surfaces.
I open it in Mesh lab where it looks fine and tells me there are no non-manifold surfaces, then I open in Blender trying to follow the tutorial. None of those nice remove duplicate surfaces or check for non-manifold surfaces seem to be available to me. I have downloaded and installed python along with it, but these options don't appear.
What can I do? I have a model that looks fine in 3 applications but looks decidely iffy when I view it on the shapeways viewer. Tired and frustrated and would appreciate any help.

Thanks

  • Attachment: 05body.stl
    (Size: 2.72MB, Downloaded 136 time(s))

Re: Blender: How to create meshes without tons of n-manifolds [message #3331 is a reply to message #2238 ] Thu, 12 March 2009 09:56 UTC Go to previous messageGo to next message
avatar PeterHermans  is currently offline PeterHermans
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Fixed it using magics. There were some overlapping poly's and open edges.

However, I have a model that was 100% ok in magics and still does not pass the Shapeways validation (inverted normals) so I'm not guaranteeing success.

Oh and you have some very thin areas (thicknesses of 0.6mm and less) that might not come out ok. It is best if you thicken those to at least 1mm.

Re: Blender: How to create meshes without tons of n-manifolds [message #3333 is a reply to message #3331 ] Thu, 12 March 2009 10:03 UTC Go to previous messageGo to next message
avatar Joseph O' Connor  is currently offline Joseph O' Connor
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Thanks for that
I now need to move on to 2 other files that still won't pass the shapeways tests.
Again, I have removed the double vertices but no non-manifold surfaces show up.
When you know there are no non-manifold faces to find, for me with very little mesh experience it makes finding the real problem almost impossible.
Re: Blender: How to create meshes without tons of n-manifolds [message #3342 is a reply to message #3333 ] Thu, 12 March 2009 17:39 UTC Go to previous messageGo to next message
avatar AO  is currently offline AO
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Joseph,

If the file is fixed with magics then yoy just have to open the file in meshlab and save it again as stl.

Aparently shapeways needs another type of stl, wich what or how I don't know, but it worked for me.

Greetings AO
Re: Blender: How to create meshes without tons of n-manifolds [message #3349 is a reply to message #3342 ] Thu, 12 March 2009 18:59 UTC Go to previous messageGo to next message
avatar Joseph O' Connor  is currently offline Joseph O' Connor
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I am not famiiar with Magic.is it Magic 3D?
I have two other files that are resolutely refusing to be acceptable. I don't want you fix them (yet) as I would rather find the tools to solve it myself and learn in the process.
Proving time consuming though.

Thanks
Re: Blender: How to create meshes without tons of n-manifolds [message #3355 is a reply to message #3349 ] Fri, 13 March 2009 10:16 UTC Go to previous messageGo to next message
avatar AO  is currently offline AO
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Hi Joseph,

Peter fixed it with magics from Materialise wich is I think a very specialistic and expensive piece of software.
But very good and fast.
Just post your files if you have problems. There's always somebody that finds pleasure in helping others.

Greetings AO
Re: Blender: How to create meshes without tons of n-manifolds [message #3357 is a reply to message #3355 ] Fri, 13 March 2009 15:20 UTC Go to previous messageGo to next message
avatar Joseph O' Connor  is currently offline Joseph O' Connor
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Hi
Deep frustration setting in.
The file is attached. I have rebuilt it and checked for errors but cannot find any in the 3d Data, Can't find any non manifoldness about it either.
On another part I removed some blended surfaces and that seemed to solve the problem. not with this one unfortunately.
I would appreciate it if someone had the time and patience to have a look at the file and see if it can be fixed.

Thanks

Re: Blender: How to create meshes without tons of n-manifolds [message #3359 is a reply to message #3357 ] Fri, 13 March 2009 17:33 UTC Go to previous messageGo to next message
avatar robert  is currently offline robert
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Hi Joseph,

You have 3 open edges in your model. You can see them highlighted in yellow in the screenshot below.

index.php?t=getfile&id=340&private=0

Best regards,

Robert

Re: Blender: How to create meshes without tons of n-manifolds [message #3366 is a reply to message #3359 ] Sat, 14 March 2009 09:52 UTC Go to previous messageGo to next message
avatar AO  is currently offline AO
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Joseph,

This file is printable, check the size if you upload.
I didn't do it.

Greetings AO

  • Attachment: headinner.stl
    (Size: 2.16MB, Downloaded 136 time(s))

Re: Blender: How to create meshes without tons of n-manifolds [message #3385 is a reply to message #3366 ] Mon, 16 March 2009 13:57 UTC Go to previous messageGo to next message
avatar Joseph O' Connor  is currently offline Joseph O' Connor
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Thank you very much for that. I spent a day in blender trying to fix it but couldn't get my head round it.
Re; The scale. The file needed to be reduced to .941 of the size you sent me in order to get it back to it's correct size. Funny scale that. Is there a scaling issue when importing into certain software that would send it off ever so slightly like that?
Anyway, its off to shapeways now with the other 11 parts that make up its assembly. This is my first with Shapeways. I'm hoping its all ok from hereon.

Thanks again
Re: Blender: How to create meshes without tons of n-manifolds [message #3405 is a reply to message #3385 ] Wed, 18 March 2009 08:48 UTC Go to previous message
avatar AO  is currently offline AO
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Joseph,

Thanks for the info about the scale. I have a setting somewhere wrong and I have to find out what or where.
I new it can be something like 10 percent.
Therefore I mentioned to check the scale, just in case.

Greetings AO

 
   
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