Creating a MD-SSM for Subtalar Joint

[Lyk]

Hi, I want to creating a MD-SSM for Subtalar Joint.

Currently, I would like to complete a preliminary experiment using ShapeWorks. I have 20 cases of talus and 20 cases of calcaneus from 10 individuals.
(All files are in STL format.)

The first problem I encountered was: how to import my STL model.
My method:

1. I created an excel like below(Name: “Talus&Calcaneus”):
   

   

2. I opened ShapeWorks 6.5.1, click “File” - “Open project” - select the excel which I just created (“Talus&Calcaneus”).

3. Then I got the first Problem: why there is nothing in my screen?
   

   

[Lyk]

Oh, furthermore all calcaneus bons and talus bones are saved in two different folders.

[Lyk]

I tried a different approach:
by creating a “New Project,” importing five STL models of the talus, saving it as a Spreadsheet (xlsx), and manually editing this Excel file ( add a column for shape_2 along with the file location for the calcaneus).
Finally, when I opened ShapeWorks, I was able to obtain an image that combined the calcaneus and talus.

But, when I trying to save it, it shows like below:

Could you please tell me how to fix it?
Thx!

[Lyk]

One more question~

At the beginning, the spatial positions and directions of the STL models we input were all different.

Should we align these models? If so, how should we proceed with the alignment?

the alignment part let me feels a bitconfused ; how should I choose?

I saw in your demo video that all the bones were in the same pose when they were introduced into the program.

[amorris]

Can you try saving as swproj (json) instead? I’m not sure what the xlsx zip stream problem is.

You can try setting the alignment to Iterative Closest Point, but this is generally for smaller misalignment. We don’t yet have tools in ShapeWorks to deal with very large misalignment. You might try aligning them manually in a different tool first.

[Lyk]

Thank you for your reply, and it realy works!
( I mean saving as swproj format file)

Next, I continue to try to create MD-SSM.
In the Optimize section, my Settings:

After the run I encountered an error:

How can I fix this error?

The result of Optimize is shown in the figure below, I found that some models were not aligned very well (e.g. 009), will this affect the result?

Thank you very much for your help.
Could you please tell me how I can fix the error of particle vector?

Best regards,
Lyk

[Lyk]

The above question still exists. However, when I try saving the software in “SWPROJ” format, the “Error” no longer appears, although I’m not sure if this counts as a resolution.

Also, after obtaining the “OPTIMIZE” results, I attempted to export the generated MD-SSM model. I right-clicked the model and selected “Export Mesh”

at this point the following error message appeared:

Do you know how to prevent this error from occurring, or what I should do instead?

Hope to receive your reply, thank you!

[amorris]

You can ignore the error about the particle vector size being different.

Yes, if some of the shapes are not well aligned, it will affect the result. You will have to examine the PCA modes to see.

[amorris]

Do you know how to prevent this error from occurring, or what I should do instead?

Unfortunately, there doesn’t appear to be a stack trace in your error message that would help us track it down. However, it sounds very much like this:

Program crashed when exporting the mean mesh as stl file by right click in the analyze panel, the mean mesh could be exported successfully though

This should be fixed in the development version of ShapeWorks:

Release Development Build for Windows · SCIInstitute/ShapeWorks