Coordinate systems in mass properties - evaluation of position center of gravity

3D Design
1

Hello 

I want to evaluate the position of the center of gravity as well as the inertia matrix of an assembly for integration on a robot. When I use the "Mass Property" tool in "Evaluate", I see 2 different marks on the image below: the mark represented by the trihedron at the bottom left (which corresponds well to my FLANGE ROBOT mark - and which I can attach or not to its origin via the options in the "ground property") and the mark with the trihedron in the middle of my room and I have a little trouble understanding its meaning/origin and whose orientation seems doubtful to me (obviously not too orthonormal ...)

Could you enlighten me? 

 

 

 

for me, apart from my starting geometry ... How to Make a Sort to Align Axes


centre_gravite.jpg
2

Hello charlesir,

Well, the 2 trieds, so one is the center of your assembly and the other is your origin in space, your zero point.

Simply.

Your assembly will move if you modify your part or add another one to your assembly.

Have a nice day.

@+.

AR

 

1 Like
3

Hello@Charlesir

For me what I see in the picture shows that you didn't ask for your CG to be displayed. The evaluate function is correct but  the trihedron has nothing to do with the CG.

In the attached image you will see that there are at least 3 types of CG representation

The overall GC

the CG of a sub-SAM

the CG of an individual piece.

The cgs move dynamically but they are only displayed in the new position when you stop your part movement with your mouse (or refresh with the red-green icon.

You have a lot of other possibilities including defining a user CG so that you don't have CG icons everywhere in the online help use "Center of gravity icons" 

Since I do a lot of complicated cutscenes, I can see at any moment the impact of the modification of a part on the global CG or a sub-ASM.

I took an example where there is no confidentiality  ;-)  to illustrate

Kind regards


les_differents_cg_-_2020-11-10_11_25_47-window.jpg
2 Likes
4

It works well indeed. 
Thank you so much for sharing
Kind regards

1 Like
5

Hello Hazelandpine8,

If your answer to your question is favorable, you have to close the question, ...

Regards.

AR.

1 Like
6

Hi all 

Sorry for my late reply, I was a bit overwhelmed. 

@Zozo_mp: thank you for the clarifications, indeed I didn't know.  There are still other representations of the different GCs. See the SW help you provided me. 

@A.R : The trihedron at the bottom left is only there to indicate the axes related to the origin (present in the Feature Manager) of my part/assembly. The other trihedron is linked to the center of gravity of my part/assembly. Nevertheless, I don't understand why the axes between the CG coordinate system and the coordinate system linked to the origin are not collinear and/or in the same direction, especially since the CG coordinate system is not orthonormal. Any idea? 

1 Like
7

Hello Charlestr,

Thank you for your clarification, cordially.

AR.