Center of gravity of each of parts in assembly

[Anonymous]

Hello,

I have created assembly (lets call it main assembly) in which there are 4 other assemblies (lets call them sub assemblies).

Now in the main assembly document i want to display center of gravity of each of the sub assembly.

When i open each of the sub assemblies and turn on center of gravity of each of them, when returning to main assembly view it displays center of gravity of main assembly, not of each of the sub assemblies.

Im asking for this because i want to create a drawing of main assembly and add dimensions of each of the sub assembly centers of gravity and unfortunatly just as in assembly view, when i want to display center of gravity i can do it only for the main assembly not for each of sub assemblies.

[pcrawley]

I think the C of G is calculated for the current document only (i.e whatever you have open).

If you want a CofG that you can include on drawings from multiple sub-assy's then you might have to create a workpoint at the correct location.

In each of your subs, create a workpoint and call it say CofG.  Constrain the workpoint to the origin planes, then use/adapt the following iLogic rule.

------------------

'Error trap: Look at the CofG, and if it returns an error, there are probably no parts in the assembly!

Try

    centerPt = iProperties.CenterOfGravity

Catch

    MessageBox.Show("Assembly has no mass.", "iLogic", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)

End Try

'CofG is valid - move the workplanes accordingly.

'CofGx, CofGy and CofGz are assembly constraints that locate the "CofG" work point.

'centerPt is an internal variable that contains x, y, and z location data.

'Update the assembly constraints to the new center of gravity:

    CofGx = centerPt.x

    CofGy = centerPt.y

    CofGz = centerPt.z

'Run the "Update" command in Inventor:

iLogicVb.UpdateWhenDone = True

------------------

Files attached if you need something to reference.  (Just move the block around and then run the rule - the CofG workpoint updates according to the new sub-assys CofG.

[Terry.VandenDungen]

My work around was to create a small ball and color it. I modeled it as reference so as to not add any mass. Then constrained it to the COG of the part I want to see in the assembly. This also has the benefit of adding it to as many parts / subassemblies as I desire.

[SER4]

In case anyone is looking for how to get a Work Point into a Part at the CoG:
https://forums.autodesk.com/t5/inventor-forum/center-of-gravity-as-work-point/td-p/2451558
You will have to remove the "Set" 'function' (operator?)

[J.F.Wedema]

But how did you constraint that part to the COG? or did you constraint it to the origin planes with the offset of the COG? how does the ball follow your COG when the assembly changes (and with it, the COG)?

Francis

[Terry.VandenDungen]

I must have used an offset. So it would not have followed the model as it changed. However, at the time the model was complete and I needed something for the drawing. I have since found the proper way to display COG in a drawing view. It does not follow our COG symbol, but I created a sketch symbol that I can snap it to the COG so it should follow it as it moves.

Thanks for the interest.