Professor Matt Zucker suggested I look into the possibility of importing a volumetric mesh into ANSYS. A volumetric mesh based on my fibrin clot .stl files would be a much more true-to-life rendition of the clots I fabricated, compared to my crude stick models. Below I will outline the workflow I have developed to accomplish this goal, largely through trial-and-error.

The first and most crucial step is to convert an .stl—which is a shape file—into a filled, solid body. As it turns out, ANSYS is much more punctilious than even the typical 3D printer as regards an error-free input; a file accepted by the printer could still be rejected by ANSYS.

Solidworks can perform the surface-to-solid conversion, but sets a hard 20,000-facets limit on the complexity of the shape file it will accept. On my part meeting that requirement necessitates highly aggressive mesh reduction. MeshLab unfortunately has trouble retaining the shape of the original file when asked to reduce aggressively, so I turned to Meshmixer instead. This software has a function Edit→Make solid. Lowering Solid accuracy and Mesh density usually results in something that at least resembles (if not particularly faithfully) the original shape, and does not have too many awkward sharp angles that ANSYS will refuse to mesh.

Next up: repair in Fiji and at https://cloud.netfabb.com. In particular, make sure to close holes and delete self-intersecting faces. This process could take many iterations. Trial-and-error is our new best friend today.

Now import this repaired .stl into Solidworks. In the import dialogue box, select .stl as the file type, then within options, choose import as solid body. N.B. mine may not be the exact wording you will see. If Solidworks refuses, go back to the previous step. If not, allow Solidworks to run import diagnostics. If errors are detected, also return to the previous step. Sorry.

If you have come this far, save the solid! as a .igs file—remember to select export as solid within the option dialogue box.

Launch ANSYS. Import this .igs file. Accept the default import settings unless something goes wrong.

We can begin meshing. Please stay tuned for updates on this front.