1D Simulation Terminated by Negative Area

Hao Mu · Post by **Hao Mu** » Thu Mar 05, 2020 3:18 pm

I was running a 1D simulation on a model of the human pulmonary arteries. SV prompt error massages for both "Create FIles for Simulation" and "Run Simulation." The error message is copied below, and the log files are attached.
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ERROR: The area of segment 'Group2_Seg1' is negative.
Terminated.
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The model was created using paths from Clinical Case Studies: Healthy Pulmonary. Only the main, left, and right pulmonary arteries were segmented. The simulation parameters and inflow data are measured from animals studies (rats) done in my lab, because we do not have any CT data for rats.
I am not sure if is the mismatch of the vessel size and velocity data or other issue causing the problem. Could anyone give me some suggetion? Thanks in advance!

Best,
Hao

David Parker · Post by **David Parker** » Thu Mar 05, 2020 6:24 pm

Hi Hao,

In the generate-1d-mesh.log file I see a couple of warning messages

Code: Select all

[generate-1d-mesh] WARNING - Ain < Aout for group id 0, face name 'cap_LPA'
[generate-1d-mesh] WARNING - This will cause problems for the 1D solver so setting Ain = Aout
...
[generate-1d-mesh] WARNING - Ain < Aout for group id 0, face name 'cap_LPA'
[generate-1d-mesh] WARNING - This will cause problems for the 1D solver so setting Ain = Aout

I'm not sure if this is causing the solver to fail though.

The problem might indeed be a mismatch of the vessel size and velocity data as you suggested. The solver assumes CGS units (the parameter values displayed in the SV 1D Simulation GUI are in CGS). If the units are consistent then you could try reducing the time step (see http://simvascular.github.io/docs1DSimu ... tml#solver).

Cheers,
Dave

Hao Mu · Post by **Hao Mu** » Fri Mar 13, 2020 9:07 am

Thanks! I tried a very small time step with shorter vessels. It worked and I saw results files (.dat) in the project simulation folder.
However, I could not convert result and the result panel looks different than the one shown in the 1D Simulation Guide. The screenshot is attached.

: SImvascular 1D panel.png (76.81 KiB) Viewed 158 times

I am using Simvascular 2019.08.09 (MITK 2018.4.2 VTK 8.11 ITK 4.13.2 Qt 5.11.3) on Mac 10.12.6. What should I do? Thank you very much!

David Parker · Post by **David Parker** » Sun Mar 15, 2020 3:35 pm

Hi Hao,

Please download the 2020.02 version of SV. The latest version has all the functionality needed to convert results.

Cheers,
Dave

1D Simulation Terminated by Negative Area

1D Simulation Terminated by Negative Area

Re: 1D Simulation Terminated by Negative Area

Re: 1D Simulation Terminated by Negative Area

Re: 1D Simulation Terminated by Negative Area