Ability to Override Center of Gravity

[jtylerbc]

My company often deals with imported files.  As a heavy transport / heavy lift company that also builds its own custom equipment, these can range from models of the customer's cargo to components of a hydraulic system supplied by their manufacturers.

Currently, we can override the mass of the imported models so that we can get a correct total weight.  We can't currently override the coordinates of the center of gravity to correct it.  Many of these items are made up of multiple materials, and may have details removed from them before they are sent to us.  As a result, it is not usually a matter of simply setting the material and getting a correct CG.

It would be very useful to us to have the ability to directly override the coordinates of the center of gravity.  We often have documentation of the CG location from our customers' drawings or from purchased-part catalog data, but currently do not have an easy way of entering that data into Inventor models. 

[laptop_geek]

We do the same thing often when we are dealing with customers data.

The easiest way to fix this is as follows (Note that if you import an assembly the process is similar, just don't create a sperate assembly):

Demote the imported file into its own sub-assembly

Make the imported part/parts phantom and override the mass to 0

Insert a dummy part in the sub assembly and make its origin the CG of the imported part

Override the dummy parts mass and set it equal to the imported parts mass.

Note that this only works for the mass and CG properties. If you need to override any of the other properties this method will not work.

This is a time consuming and tiresome workaround and it would be very nice if I was allowed to do this by simply override the CG in the part.

[DWhiteley]

You can override the mass in iProperties but not the COG. This is something you would want to do for, say, a gearbox supplied b y a 3rd party, where you would model the "LUMP" and override the mass and COG. SWX can do this already.

[jtylerbc]

This idea is a duplicate of an existing one.

http://forums.autodesk.com/t5/Inventor-IdeaStation/Ability-to-Override-Center-of-Gravity/idi-p/47428...

If you kudo this one, please make sure to vote for the older one as well.

[drawings]

Also, shrinkwraps and representations should capture the masters mass & cg. This is needed where detail (internal voids) are removed as well as when it consisted of multiple materials.

[ldrozdz]

I run into this post and though I would add my 2 cents. I add a sphere to my parts in location where spec calls out COG. I do it by adding a workplane offset in one direction (lets say x), add a sketch on it and place a point with Y and Z dimensions. Then I create a sphere by selecting a workplane and point. On a drawing I find the sphere solild ina browser and turn hidden lines on it. I override part's mass property. I hope it helps. 

[dan_szymanski]

Accepted idea [37898]. Thanks!

[dan_szymanski]

We are refining procedures around idea status.  Changing this to Future Consideration.

[alessio.luis]

So, how far is this future?

[dusan.naus.trz]

Hello. When will it be implemented?

[dusan.naus.trz]

https://help.solidworks.com/2018/English/SolidWorks/sldworks/t_override_com_point.htm

http://www.rickyjordan.com/2012/09/solidworks-2013-mass-properties.html

[dan_szymanski]

Let me reply to your question, with another question. How often would you find yourself doing this?

[Sergio.D.Suárez]

When we have imported components, in many cases they are simplified solids and do not have the real internal empties. This is why the inventor's center of gravity is wrong with respect to the true center of gravity of the imported equipment. Inventor allows you to manually modify the mass value of a part, it should also allow us to manually modify the coordinates of the center of gravity, since in the master assembly that uses these components there will be an inherited error in the global center of mass.

Set center of mass should be available in the inventor API

CenterOfMass -> Gets and sets the center of mass.

This could be solved by creating a surface from a face of the imported solid (with thicken / offset -> mode surface -> offest = 0), then remove this face to convert the solid into a surface group, now we sew the surfaces and keep as surface.

Now we create a small solid sphere with center in the coordinates of the real center of gravity that we specify.
Finally we manipulate the value of the mass calculated by inventor.

[swalton]

While you wait for the 3-6 years for Autodesk to implement this idea, try the following:

1. Create a 1" or 1 cm cube. 
2. Set its weight to the weight of the imported component.
3. Create a new material named Weightless. 
4. Set Weightless's density to 0.0001 ( or the smallest amount Inventor accepts).
5. Assign the Weightless material to the purchased component.
6. Create a placeholder assembly.
7. Place the imported component in the placeholder assembly.
8. Constrain the unit cube in the placeholder assembly at the correct cg.
9. Use the placeholder assembly when you need accurate cg locations and weights for the purchased component.

[Pate.MacKenna]

There is an existing idea on the forum for this topic: 4742839

[THA_PGFS]

@ dan szymanski 

Frequently, we have loads of imported pumps, motors and valve assemblys with wrong COG's this creates issues when the parts have a large mass relative to the assembly they are in. 

[dusan.naus.trz]

Hi @jtylerbc 

I found this great video. It will help? What do you think? Or what do others think?

https://www.youtube.com/watch?v=EYNt7KNDxps

[TONELLAL]

Always in Future consideration for now 5 years... Do you really think it will be solved one day ?

Of course, we can create an assembly containing a dummy CoG, override its mass and manually place it at the correct place... But for me it is only a workaround, waiting this bug is fixed ! (Yes, as an Inventor user I consider it is a bug, not a "limitation").

[noorman2008]

Would really like to see this fixed. 

We get an awful lot of parts from suppliers as STP / SAT files. Often ending up partially with solid bodies which then utterly destroy the CoG location.

Without an override for this lcation the weight distrubition goes completely off.

Has resulted already in some minor mishaps where something toppled over, while the models said we had enough margin for the support legs.

As the CAD guy I look stupid, but only solution is stupid workarounds.