stl geometry

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Mohammadreza Rezaie
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Joined: Fri Nov 24, 2017 12:48 am

stl geometry

Post by Mohammadreza Rezaie » Mon Jan 20, 2020 4:25 pm

Dear Experts,

I added a new bodyset to my model and the geometery was in .stl format.
When I open my model in OpenSim 3.3 everything is correct but in OpenSim 4.0 GUI, that new geometery is broken.
the first image is OpenSim 3.3 GUI and the second one is v. 4.0
1.jpg
1.jpg (4.31 KiB) Viewed 374 times
2.jpg
2.jpg (11.43 KiB) Viewed 374 times
Any help would be greatly appreciated.
Cheers

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Ayman Habib
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Joined: Fri Apr 01, 2005 12:24 pm

Re: stl geometry

Post by Ayman Habib » Mon Jan 20, 2020 5:42 pm

Hello Mohammad,

OpenSim 3.3 used vtk to parse STL files so it was able to handle a variety of files, in version 4.0 we dropped vtk since we're using a different tool/package for visualization, instead we use simbody's native STL parsers. These seem to handle a smaller subset of STL files, in particular, if the file contains more than one solid then it's likely not going to work. In this case I'd suggest you split the solid into different STL files and include them individually. While this may have been documented in 4.0 release notes, we understand the inconvenience and have ideas to fix the issue. Please file a bug using the bug reporting feature in the software and attach the stl file so that the issue is tracked and prioritized.

Best regards,
-Ayman

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Mohammadreza Rezaie
Posts: 412
Joined: Fri Nov 24, 2017 12:48 am

Re: stl geometry

Post by Mohammadreza Rezaie » Tue Jan 21, 2020 4:12 pm

Dear Ayman,

Many thanks for your reply.
I split my 3d model in different solids and fortunately, the visualizer showed the geometries, correctly.

I want to ask a new query regarding the axes of geometries. For example in the femur body, the axis is located in the femoral head.
is it possible to change the axis location of a geometry? in my 3d model, the axis is located in the middle of the body (somewhere near the body mass) and I want to set it in the most proximal part of that (like tibia or femur).

Your help would be greatly appreciated.

Cheers

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Ayman Habib
Posts: 2252
Joined: Fri Apr 01, 2005 12:24 pm

Re: stl geometry

Post by Ayman Habib » Wed Jan 22, 2020 12:30 pm

Dear Mohammad,

In most cases, in our examples, the geometry mesh file is attached directly to the Body frame, however the model format allows for the introduction of an offset between the the Geometry frame and the body frame. In version 3.3 the rotations and translations were exposed in the GUI to allow you to move the Geometry w.r.t. the Body using the property editor in the lower left panel of the application, in version 4.0 this is also possible by defining a new Frame with the desired transform (translation/rotation) and then attaching the mesh to it.

Hope this helps,
-Ayman

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Mohammadreza Rezaie
Posts: 412
Joined: Fri Nov 24, 2017 12:48 am

Re: stl geometry

Post by Mohammadreza Rezaie » Wed Jan 22, 2020 2:25 pm

Dear Ayman,

I appreciate your help.
My problem was solved completely.

Cheers

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