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Problem with scanned model's face partitioning
Posted 28 juin 2016, 10:34 UTC−4 2 Replies
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Hi,
for my engineering thesis I need to analyze denture model (obtained from 3D scan) in COMSOL. The problem is that when I import my model to COMSOL it has some random face distribution and I can't apply boundary conditions precisely. Faces created by COMSOL are too big and randomly distributed.
I've found one way to get better face partitioning - create proper partitioning in some third party software, then export it as BDF file (Nastran format) and import this file to COMSOL as a mesh (not geometry like I was trying before). I've also found such a third party software - Gmsh program. But even when I create face partitioning with same number of faces as number of triangles, COMSOL still merges some triangles together and faces are bigger than they should be. Does anyone know why program ignores these thin lines visible in Mesh node and creates boundaries only from bold triangles (as shown in Physics node) ?
Is there any other way to import models with predefined face partitioning ?
for my engineering thesis I need to analyze denture model (obtained from 3D scan) in COMSOL. The problem is that when I import my model to COMSOL it has some random face distribution and I can't apply boundary conditions precisely. Faces created by COMSOL are too big and randomly distributed.
I've found one way to get better face partitioning - create proper partitioning in some third party software, then export it as BDF file (Nastran format) and import this file to COMSOL as a mesh (not geometry like I was trying before). I've also found such a third party software - Gmsh program. But even when I create face partitioning with same number of faces as number of triangles, COMSOL still merges some triangles together and faces are bigger than they should be. Does anyone know why program ignores these thin lines visible in Mesh node and creates boundaries only from bold triangles (as shown in Physics node) ?
Is there any other way to import models with predefined face partitioning ?
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2 Replies Last Post 28 juin 2016, 11:48 UTC−4
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Posted:
8 years ago
Hi,
This blog post from yesterday could help you. It aims at exactly your situation where the boundary conditions does not fit the boundary or mesh subdivision. You only need to make sure that the mesh reasonably well resolves the size of the boundary conditions.
www.comsol.com/blogs/how-to-make-boundary-conditions-conditional-in-your-simulation/
Regards,
Henrik
This blog post from yesterday could help you. It aims at exactly your situation where the boundary conditions does not fit the boundary or mesh subdivision. You only need to make sure that the mesh reasonably well resolves the size of the boundary conditions.
www.comsol.com/blogs/how-to-make-boundary-conditions-conditional-in-your-simulation/
Regards,
Henrik
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Posted:
8 years ago
Thanks for your fast reply. I'm afraid that I won't be able to customize my boundary conditions in such way using formulas (and I'm not sure if it's possible to use them in my case where I only apply load and fixed constraint to my model). I'm a beginner and my thesis supervisor never used COMSOL software so nobody can help me apart from experts on this forum. If it's possible I would like to solve this problem without any advanced options like formulas. Is there any other way to do it ? Maybe I have to use different file format or improve mesh in COMSOL after import ?
In Reference Guide I've found information that when model wasn't created in CAD software like SolidWorks then COMSOL creates face partitioning using heuristics. However when I import mesh in BDF format it should create domains from predefined face partitioning. But it doesn't for some reason ...
I've also found short movie showing how to export models created by 3D segmentation of anatomical structures from MRI/CT images in Materialise Mimics software directly to COMSOL. And in this case partitioning is perfectly preserved: www.youtube.com/watch?v=GreXD6QRlz4
Can I achieve the same effect in my case somehow ?
In Reference Guide I've found information that when model wasn't created in CAD software like SolidWorks then COMSOL creates face partitioning using heuristics. However when I import mesh in BDF format it should create domains from predefined face partitioning. But it doesn't for some reason ...
I've also found short movie showing how to export models created by 3D segmentation of anatomical structures from MRI/CT images in Materialise Mimics software directly to COMSOL. And in this case partitioning is perfectly preserved: www.youtube.com/watch?v=GreXD6QRlz4
Can I achieve the same effect in my case somehow ?