Multi-Body Question

[Anthony Podgorsak]

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

[David Parker]

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

[Anthony Podgorsak]

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

[David Parker]

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

[Anthony Podgorsak]

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

[David Parker]

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

[Anthony Podgorsak]

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

[David Parker]

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