Plane through the center of gravity

3D Design Volume Model
1

Hello to you.

I'm currently working on a cart that will be able to accommodate several pieces that will just be hung on a hook a bit like tools that are hung in a display of a DIY store, if you image the thing like me....?

So I displayed the center of gravity, but I'd like to make a shot going through this center of gravity and another point on the part, so that I can then create a constraint, you see the table?

So how do we create a point related to the center of gravity, or how do we make a plane passing through the center of gravity?

I hope I have been clear enough in my description...

See you right away.

Lucbirus

2

Hello

With this macro you'll see it's the power of force.

may the force be with you.


swp-cdg.zip
1 Like
3

wow... I don't know anything about macro.....

Can you explain to me or is it too complicated from a distance?

4

ah I found something...

When I right-click on the center of mass, it offers me to make a reference point of the center of mass, which I did.

So when I create two more points, I can make a plan. If I put this plane vertically in relation to the hook, I think I have the position that the piece will have when it is hung, right...?

1 Like
5

It's simple

1- Unzip the file

2-Open the part or assembly

3- do   outis/macro/ execute => go to the swg-cdg>application>macro folder  and  test the 2 macros.

may the force be with you.

 

1 Like
6

For a few versions, it has been possible to create a "center of mass" function on which you can cling.

it's from the Evaluate/Mass Property panel (the icon with the scale), a checkbox:

3 Likes
7

@stefbeno.

I don't have this box to tick even though I'm under SW 2018.. weird.

@OBIWAN

I downloaded RTON Zip and unzipped as requested.

on the other hand I can't find files that SW could open... I see *.swp extensions ,.. What do you open this with?

8

do   outis/macro/ execute => go to the swg-cdg>application>macro folder  and  test the 2 macros (it's a .swp file)

may the force be with you.

 


obi_wan_macro_sdg.jpg
9

@lucbirus

I don't have this box to tick either.

Let's remember that the center of mass reference point can only be activated in a part and not in an assembly. So it is only in a part that we can have dimensions driven on the ground reference point.

For the assemblies it's pifometric because when you zoom the point becomes more precise or more wrong. Is still if your assembly is static, if it's dynamic, you have it in your bone. (unless I don't know the appropriate feature)

As I do a lot of cinematics I get around the difficulty

==> I create a sketch on one or more planes
==> I make a circle that surrounds the CM
==> I leave the sketch
==> I move the object and start again for the whole run.
==> I then visualize the sketch(es) that group the point cloud

If another method exists, I'm very interested. :-)

 

10

As Steffeno says,

it is better to use the basic function integrated into Solidworks, because it will recalculate automatically with the reconstructions.

 

11

Yes @olivier42 in the assembly the CG is recalculated in auto that's for sure. But it will not be able to fix the plane in the assembly from the CG of the assembly.

 

12

A solution that works in a room (I haven't tested for assembly, but I'll say it's the same thing)

1 - Defining equations [see Log 1]

2 - From these equations, define custom properties [See Log 2]

3 - Move a plane [Pay attention to the direction and units] and apply an equation to it (In my case: = Y) [see Log 3]

4 - On this plane create a point and apply equations to it in both directions (In my case X and Z) [See log 4]

You have created a point corresponding to the center of mass and updating after each rebuild!

 

View Part - Caution - SolidWorks 2018

 

EDIT: Well ... Obviously the images don't give what I thought!, you will find below the 4 images in a slightly larger format!

https://ibb.co/jL3udd
https://ibb.co/mPHbry
https://ibb.co/mAhbry
https://ibb.co/gmOSyd

 

EDIT 2: Come to think of it, it corresponds rather well to your request! We make concrete parts (Stairs to be precise), the method explained above allows us to position the chains of the crane in order to help the sites for the handling^^


exemple_cdm_2018.sldprt
3 Likes
13

So I have the box with SW15 for an assembly.

On the other hand, I hadn't tested and it was impossible to hang on to this function whether in coin or asm mode.

I created a sketch, wanting to dimension it in relation to the COG, the dimension is controlled.

The solution seems to be to create a 3D sketch with a point dimensioned in relation to the COG or maybe we can retrieve the position of the COG from the equations and use this value to assign it to a dimension.
I tried, Sw offers in the "usable" properties the 3 coordinates ("SW-MassCenterZ") but impossible to assign it to a variable or a dimension.

14

You want a good joke, with SW15 (I tested on 14, 15, 16 and 17, it's only fixed in 17!):

For those who want the solution quickly:
SW proposes as a parameter "SW-CenterofmassZ" which is not recognized but if you force the text to "SW-Center of gravityZ" it works.

1 Like
15

@stefbeno

Really too strong Stef

[[ SW proposes as a parameter "SW-CenterofmassZ" which is not recognized but if we force the text to "SW-Center of gravityZ" it works. ]]

Do you have any idea if it gives the ref on the three axes or on a single axis in which case you just have to do 3 equations if I understood correctly

I've never used equations  so don't be surprised by my question (don't bang your head NOOooonnn)

EDIT: sorry I hadn't seen the parts  of @Macro227 which are a quasi tutorial. Thank you Marco227

16

I'm on SW2018 sp3 and it offers me "center of gravity" (and not "center of mass")

Of course negative values don't help, you have to add an x-1 to reverse it

17

Like stefbeno  create the center of mass of the part by checking the option and then right-click on that center of mass and create a center of mass point and snap to it. (test 2016)