simtk.org

Hello,

I am attempting to model cannulated flow inside an extracardiac TCPC - currently working with an idealized PA model. To get the methods down, I am currently using a simple cylinder for the PA and a simplified discharge lumen designed in SolidWorks. (https://www.dropbox.com/sh/v9n15za55cir ... oQb3a?dl=0)

When I import them as a single model - the SV facial extraction fails to differentiate between the inlet of the discharge lumen and the walls.

When I import them separately as segmentations, the onboard modeling modules fail to create a single model from the two segmentations.

My question is twofold:
1. Is SimVascular able to handle multi-body simulations?
2. Are there any other onboard facial extraction tools? Or would I need to write a code to manually extract the faces?

This is on SV 19.01.27 release with Windows 10

Thanks in Advance,
Anthony

Hi Anthony,

I downloaded your models and had a look at them in SimVascular. SimVascular should be OK with models with multiple regions (disconnected geometry) I think.

The centre_PA model looked ok, SimVascular extracted five faces that seemed to be correct. However, when I tried to mesh it the mesher failed so there is still something with the model that is upsetting SimVascular.

The center_limen is fine, correct number of faces and meshed ok.

The CentreAlign model did not work, too many faces extracted.

Could you please upload the models in xmt_txt format? Maybe there is a problem with the translated the models.

Cheers,
Dave

Hi David,

The centre_lumen file is all good, it was primarily the centre_PA model that was giving me difficulties.

The three files have been uploaded to the DropBox link as .x_t parasolids (https://www.dropbox.com/sh/v9n15za55cir ... oQb3a?dl=0)

Thanks again for your help,
Anthony

Hi Anthony,

I was able to read in the Parasolid files (after renaming them to ._xmt_txt) but the SV Model module did not extract the faces correctly.

The models are very small so I think there may be a scaling issue. Could you please scale them by 100 and then write them out as ._xmt_txt files and upload to DropBox?

Thanks,
Dave

Hi David,

The models have been uniformly scaled by 100, written as ._xmt_txt files, and are in the DropBox folder from the link below.

https://www.dropbox.com/sh/v9n15za55cir ... oQb3a?dl=0

Thank you again,
Anthony

Hi Anthony,

Thanks for the new models!

I was able to load the all models into SimVascular and extract the faces correctly, although they were not classified correctly as cap/wall, had to manually set the face names and type (cap/wall). The CentreAlign model has duplicate faces for the interior because how the Brep model represents interior faces.

The centre_PA.vtp model you sent me also had the faces extracted fine but it wouldn't mesh. Were you able to extract faces correctly for that model?

Cheers,
Dave

Hi David,

For the centre_PA model, the faces extract properly with me manually setting cap/wall. The only issue that I am having is with the meshing of that model specifically.

The only sort of conjecture that I have is that it has something to do with the hollow portion of the model, however I am unsure as to why that would be causing issues with the tetgen module.

Best,
Anthony

Hi Anthony,

So the faces are being identified but not classified as wall or cap. I'm not sure if that is normal for polydata models or not, I will check.

The tetgen mesher is complaining about intersecting faces, this might be a tolerance issue. Could you please upload the centre_PA model (STL or VTP) to DropBox again (I don't have the model where I am working today)?

I will dig into the code to try to figure out what the problem is.

Cheers,
Dave