Home » Support » 3D Design » The problem of importing from scientific imaging systems
Search Search  
Show: Today's Messages    Show Polls    Message Navigator
The problem of importing from scientific imaging systems [message #10287] Sun, 28 February 2010 08:32 UTC Go to next message
avatar kshort  is currently offline kshort
Messages: 4
Registered: August 2008
Go to my shop
Junior Member
Hi all,

I have an interesting problem, basically revolving around non-manifold issues.

I have datasets that are from tomographic scans, which I make a solid binary .bmp stack from. I then use another piece of software to create an isosurface of that, and then I generate a VRML from that isosurface.
I can get a detailed model of 450000 faces, and it is watertight according to AccuTrans3d, and there are 7 edges (14 vertices) shared with 3 or more polygons. Not bad for a model of that complexity, I thought.

.. but blender lights the model up like a christmas tree when I do a non-manifold check (1.35 million edges selected out of 1.35 million). I figured it might be an issue with Normals, so I checked in 3DSmax, and sure enough there were normals facing in, and others outwards. I unified these (automatically) and from my quick look, it seemed to work.

Now when I upload the model, i get a manifold problem, and the same recurring issue with the manifold selection in Blender.

I can't manually generate this mesh, because it is generated from biological data, so I need to fix it. However, I don't know what the manifold issue is that Blender is detecting. It is a single object, tested as watertight.

Can anyone point me in the right direction? The Shapeways tute on Manifold problem ressureciton didn't really help because my problem is so massive.

thanks for any pointers
Kieran
Re: The problem of importing from scientific imaging systems [message #10289 is a reply to message #10287 ] Sun, 28 February 2010 10:12 UTC Go to previous messageGo to next message
avatar GHP  is currently offline GHP
Messages: 118
Registered: October 2009
Go to my shop
Senior Member
Did you deselect all vertices in Blender before doing the non-manifold selection? For some reason, it doesn't clear the current selection, which certainly confused me at first.

Also, you want to make sure that you've removed all duplicate vertices before checking, with the limit set to zero instead of the default (0.001, I think). Because the VRML uses metres as the units, your numbers will likely be quite small, and both Blender and Shapeways are imprecise when checking for duplicates, so close vertices will be merged.

[Updated on: Sun, 28 February 2010 10:18 UTC]

Re: The problem of importing from scientific imaging systems [message #10291 is a reply to message #10287 ] Sun, 28 February 2010 16:34 UTC Go to previous messageGo to next message
avatar aoster  is currently offline aoster
Messages: 12
Registered: November 2009
Go to all my models
Junior Member
Hi,
I made a quick tutorial how to create a printable file with netfabb:

http://www.shapeways.com/forum/index.php?t=msg&goto=1009 8#msg_10098

bye,
Alex

[Updated on: Sun, 28 February 2010 17:19 UTC]

Re: The problem of importing from scientific imaging systems [message #10302 is a reply to message #10291 ] Mon, 01 March 2010 04:25 UTC Go to previous messageGo to next message
avatar kshort  is currently offline kshort
Messages: 4
Registered: August 2008
Go to my shop
Junior Member
thankyou all for your help.

I think Aoster might be onto something with netfabb..

I'll keep you all updated!
Re: The problem of importing from scientific imaging systems [message #10303 is a reply to message #10302 ] Mon, 01 March 2010 05:24 UTC Go to previous message
avatar kshort  is currently offline kshort
Messages: 4
Registered: August 2008
Go to my shop
Junior Member
Alex (aoster),

Your method worked! I think that NetFabb treatment should be mandatory for all people making models for shapeways!!

Thankyou very much Alex, and thanks everyone else for offering advice.

all the best,
Kieran

 
   
Previous Topic:Yet another topic on manifold errors
Next Topic:How do you fix inverted normals on rhino

Logo

Hello.

We're sorry to inform you that we no longer support this browser and can't confirm that everything will work as expected. For the best Shapeways experience, please use one of the following browsers:

Click anywhere outside this window to continue.