I create CAD files in a CADing software and need to import them into a meshing software for my CFD simulations. Cracks appear in the geometry during the process. A micron level confirming to boundaries is essential. It is therefore too difficult to find all such cracks manually and repair them. I have a centimetre sized object. Looks like the appearance of cracks is inevitable and softwares do not seem to provide an automatic size based crack repair (understandable, as the software is supposed to mesh, not repair boundary mistakes) Proving to be a real spot of bother. Thanks in anticipation.
I recommend to create the CAD model as solid model (instead of a surface model). The definition of a solid model includes a "closing condition", which avoids any holes or cracks.
Kind regards,
Mario
I suggest to put an optimum level of tolerance i.e. if your geometry in centimeter then micrometer tolerance is good. After providing an appropriate tolerance then software automatic build up geometry in such that way with consideration that the hole which is less then tolerance that will automatic filled up through build up topology repair.
Regards
S.Shukla
I would suggest you to import your geometry into MeshLab ( Free Software). Then there is a tool (Fill Hole) there which you can use to close your geometry.
Regards,
Mahdad
Most of the meshing tools are generally provided with CAD clanup tools (Edge equivalance tool in your specific case).
If that is not the case with your meshing software, you can try what Mahdad Talepour suggested or try changing the CAD (igs/stp/nas/hmascii etc) format etc.
If thats not possible too, try surface meshing anyway and in the end merge the free nodes at cracked regions. (Choose tolerance carefully while doing this!)
I am grateful for the suggestions that have and will come up.
It looks as though I would need to work at the CAD level, all in all. I have a .stl file which I have been trying to process further. I am not sure at the moment, but the information about the object being "solid" as against being a "surface" is already in the file. The way it was prepared, they merged two separate solid sections. In the process, they have ended up having a few 10 to 100 micron sized gaps when they mated surfaces of the original objects. I suppose this cannot be repaired, unless I go back to CATIA and redo the whole thing.
If you have an STL file, you can convert the STL file to IGES. Then you have a surface model with a big number of surface elements. These surface elements can be merged and after that, the merged surface model can be converted to a solid model by use of a Fill-Function. It might be a problem, that the IGES file has some "open" surfaces, so that the merging and filling process does not work automatically. In this case, the open surface spots must be repaired by hand, or you can adjust the computation tolerance in a way, that the failure distance is not considered by the system anymore.
Another possibility is to use automated repair functions in the CAD system. CATIA provides a "HEaling" funktion in the workbench Generative Shape Design. With this function, it is possible to repair failures of surface models.
Kind regards,
Mario
- Badges
- Science topic