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STL file export and import creates strange defect
Posted Jan 30, 2020, 2:36 a.m. EST CAD Import & LiveLink™ Products for CAD, Mesh, Equation-Based Modeling Version 5.4 1 Reply
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Hello,
I am generating a geometry by solving a system of PDEs in COMSOL and exporting a filtered volume plot of the variable of interest as an .STL file.
My issue is that once I import this .STL file into my new COMSOL project the geometry exhibits issues that look a lot like "stray nodes" or something like that. One or two points appear to be off by several meters and this results in problems. Studying the .STL file in other software that can open the format as 3d geometry it looks fine. Reading the ASCII format file and checking the vertices, there should be no point that corresponds to this stray vertex that I see in COMSOL. This problem does not appear to happen every time, but often enough to be a problem.
Does anyone know what causes this and if it can be mitigated? Otherwise, does anyone have any suggestsions for an alternative way of creating this geometry?
The strange line out from the main geometry is the defect which I am talking about. For some geometries this defect disappears with the use of the "Simplify mesh" setting in the geometry import. For some it does not.
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Hello Daniel,
It seems that the issue you experience when importing the STL file to a geometry is that the visualization mesh of the imported geometry becomes slightly corrupted. This does not necessarily mean that there will be problems when meshing the geometry but it sometimes indicates that the imported geometry is of bad quality.
In the latest version of COMSOL Multiphysics (5.5) there are several new features that I think would be useful for this application. We will give a webinar about these new features this spring (see https://www.comsol.com/events/webinar/How-to-Repair-and-Improve-Imported-Meshes-from-3D-Scans-76952).
If you are working with the 5.4 version there are also some tools available that can be useful to create a good quality geometry from an STL file. Please contact the COMSOL support team (https://www.comsol.com/support) if you need further assistance.