Having different cm markers when I apply the same function in one design?

Well, first: Never use the cm-marker for any function expressions! Let Adams handle that and use only user defined markers for force and other expressions.

And second, using the click and point (as in Along Axis Orientation) is a PITA. It has no real relevance in building reusable models. As very little of the Adams/View interface is useful for that purpose. MSC and MDI has in all years neglected the need for building parameterized models in View, promoting easy click and build ways for beginners to be able to sell to novices that can now build their first planar model in 10 minutes. And then they buy Adams and after a month or two realize that they can't do anything useful in View without having to write all expressions by hand.

As an interesting side note: MSC did for a very short while had a very useful preprocessor that allowed you to click on markers and would actually create parameterized expressions from that. But they terminated that product as no one wanted to buy it while it only had 30% of the functionality implemented and customers wanted to wait until all functionality was there while MSC wanted them to pay for the reduced functionality so they could found the implementation of the remaining 70%,

That product was the bane of many a good developers at MSC.

 

As Jesper says, use different markers for different things.

If you add a marker and use it, the CM should not change.

Well there actually is an A/View that is good for building reuseable parametrized models.

They call it A/Car.

@Jesper Slattengren​ Thanks for your response! Actually, I did not use cm markers, The damper has two body parts, I want to relocate the piston endpoint, and when I change the location of the piston, the bodies get separated; then I have to make the orientation of piston and cylinder toward each other. I want to make a design variable for this purpose and, it needs parameterization in the body's orientation. I use "ORI_ALONG_AXIS" function to parameterize the dampers' body orientation. There is a problem when I add expression builder to the piston marker orientation. After adding function to the Orientation, the cm marker location and orientation will change even if I am at the same location (nothing has changed). This change is unwanted and it makes wrong results because simulation results are affected by cm markers position and orientation. my desire is to parametrize the orientation of damper bodies and keeping the initial condition constant.

@Henrik Skovbjerg​ Thanks for the response! I want to parameterize piston orientation, so I have to use the body markers; otherwise, the body won't change when I change the piston endpoint location.

If you look at the attached cmd-file you can see how to parameterize two damper parts to references. Move the references and the damper parts will follow.

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Attached Files (1)

@Henrik Skovbjerg​  Thanks a lot! Yes, My model is exactly the same. The only difference is I used points instead of reference markers. When I add ORI_ALONG_AXIS, the cm markers orientation and coordinate change. How can I avoid that?

If the geometry moves, then the CM markers will move.

In normal cases - as when just using cylinder geometry like this - you don't need to care about the CM markers. AView can re-calculate them so that they orient differently.

Of course, if you know the CM location and the inertia tensor of the two parts, then you should change them to be user defined and parameterize the cm-marker as well. Then nothing but the graphics will change when you change the reference points/markers.

@Henrik Skovbjerg​ in this case the geometry does not move, the cm marker is followed by the orientation of the origin point.

I have a damper that The Z direction of the piston and cylinder markers are already toward each other. for the purpose of piston relocation in just one direction, I have to use ORO_ALONG_AXIS. After applying this function(without changing the location of the endpoints), the Z coordinate of the markers orientation change, subsequently cm-markers change. I was wondering if there is a way to make this function without changing the initial coordinate and condition. Because I should keep the initial condition constant. There should not be any change in cm markers and also endpoints locations when I just have added functions not changing the location.

I need to understand why the markers X-Y plane rotate in Z direction after applying ORI_ALONG_AXIS when the two markers are already in the same direction. I appreciate it if you could help me with that.

The ORI_ALONG_AXIS parameterization only prescribes one axis. Adams View can rotate the item around the Z-axis depending on how the orientation is relative to global. If you want another behavior, you will have to use another parameterization. One suggestion would be the ORI_IN_PLANE, but with this you would need an extra marker on ground giving the plane direction.