Does Adams View follow the specific rule to calculate the cm marker orientation?

I have a Damper, I used ORI_IN_PLANE to parameterize the orientation of the piston and cylinder. When I apply the function I get exactly the same orientation (design variable still is the same-standard value). However cm-marker orientation is changed! Does anybody know why? how can I control that without parameterizing the cm marker. I want AView to automatically calculate the cm-marker coordinates.

0 Henrik.Skovbjerg over 4 years ago

CM-location is the same (obviously).

CM-orientation is different. It has it's Z-axis reversed, and is rotated around it's own Z-axis.

However, this does not matter at all since the inertias Ixx and Iyy are the same, and there are no off-diagonal terms.

Both setups will handle the same in dynamic analysis.
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0 fatemehh over 4 years ago

@Henrik Skovbjerg Thanks for checking the model. But when I apply exactly the same change to the main model and run the simulation, the results change! I have a translational joint and damping force inside the damper. But nothing has changed. Do you have any idea why this change happens? should I change anything else?
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0 fatemehh over 4 years ago

@Henrik Skovbjerg if you check the cylinder cm marker location, you will see that the Z coordinate has changed.
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0 Henrik.Skovbjerg over 4 years ago
The cylinder cm marker changes on the 10th digit, so the difference is 1e-10 mm. That is really of no significance, and should not result in any difference when running the analysis.

Please - if you don't like that AView changes things, then do this:

Modify the mass properties, and make AView calculate the mass

Modify the mass properties again, switch to user-entered and keep the values that AView has calculated for you.

Do any other movement of the parts. As long as you don't change the size of the geometry, the values will still be correct.
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