Center of Gravitation on drawing Main Part or Assembly

[s_hannemann]

Dear experts,

i am looking for an easy way to draw the center of gravitation on my main part. At the moment, i have to calculate the center of gravitation in the model space, create a very small plate or beam, add it to my main part, create views to add some dimensions.

There must be an easier way, im sure^^

I am thankful for any advice.

[bigcarl5000kg · Accepted solution]

Hi @s_hannemann,

because the command for the center of gravity (_astm4balancepoint) only generates its coordinates in the command line, and there is currently no possibility to use the command to put in / determine the position of the center of gravity in the drawing, it seemed that the only option was to create a dummy object (as simple as possible) to dimension its position at this point. The disadvantages are that its position (dummy object) can change, in case of a change in the model!

I recommend you to create a new thread in Idea station for Advance Steel, so that the developer can eventually deal with it. As always, without any guarantee.

[bigcarl5000kg]

Additional help - Advance Steel inserts in the model a point (Autocad object) in the place for center of gravity with each command "(_astm4balancepoint)" = more points possible, depending on model changes. 

The options:

Var. 1 - if you have no other AutoCAD basic objects (lines, circles, etc.) in the model (it is not enough to switch off only certain layers with CAD objects), you can activate such option (here translated from German) "Enable detailing of CAD objects within camera drawings" in Management Tools - see my settings under. Use filter to find this setting in your language.

Disadvantages - only suitable if there is really one AutoCAD basic object (point) in the model; the point representation in the drawing is very small - you don't always have to find it easy

Var 2. - check if the option to detailing CAD objects in Management tools (see above) is deactivated; add in your camera drawing style new line with something like "additional ACIS-body" as model object, define the representation and description; insert at the point location (center of gravity) eg. a sphere (3D ACIS object) mit eg. R=30mm (or equivalent in Inch). This object appears in the drawing and you can dimensioning the position (manuall or automatically). 

Basically, it's similar to what you've done with other dummy objects, only simpler...

[iwafb]

For what it's worth, there's already a request in the ideas station for this:

https://forums.autodesk.com/t5/advance-steel-ideas/centre-of-gravity-for-assembly-to-be-shown-in-ass...

Doubt Mr @pawelpiechnik is reading it though... In his defense, why would you want it??

[iwafb]

Also, you can use the ddptype command to change the size of points created in the model, something like:

[bigcarl5000kg]

Hi @iwafb,

until we get any response from DEV, our hair will at least be on end. I would be careful when publishing HIS name, often the reaction is to simply delete your post - probably AI in the background 😆 - ask @acbsdesign for more 😎

[s_hannemann]

Thanks for the suggestions. Why are these simple tasks not programmed? How difficult can it be to show COG in the Main Part drawing^^

[bigcarl5000kg]

Hi @s_hannemann,

definitely possible, miracles happen quickly and expect anything impossible within three days 😁.

Whenever you use the command "astm4balancepoint" to determine the position of the center of gravity, one point will be inserted in the model space at these coordinates (with each execution of this command, possibly in another place / coordinates).

Like other solutions, I got help from the AutoCAD LISP forum. LISP in the attachment automatically inserts a sphere solid object (ACIS point) in the last inserted point. Therefore, if you first execute the command "astm4balancepoint" and then this LISP (you can also create a command macro that performs both operations in the given order at once, create an icon and insert it, for example, into the Ribbon), you will semi-automatically have an object for drawing.

LISP execution command = COG (can be edited in LISP)

This LISP variant does not deal with the existence of other objects of the solid type (sphere, etc.), so with every change in the position of the center of gravity (changes in the model) you have to manually intervene and delete something - if you use it and the model is ready, there is a small probability of changing the position of the centers of gravity.

In this LISP there are several variables that you can change as needed: value PDSIZE = 10, PDMODE = 34, sphere diameter = 30)

HTH

[s_hannemann]

Hi,

thanks for the Lisp, but she doesnt work at all^^

Generates only a Point, like always...

edit: I am stupid, its working. Thanks

[bigcarl5000kg]

Hi @s_hannemann,

try to read what I wrote ... the command in Advance Steel for the center of gravity will always create a point in model space at the given coordinates. This is not suitable for drawing as a point for the center of gravity. That's why you still use LISP, which inserts a AutoCAD solid object - type sphere (ACIS body) at this point. You define this in the drawing style (new line) as visible and how, you can add a automatic description and dimensioning too. It is a replacement solution and very simple. Definitely better than other dummy objects, IMO.

HTH 😉

[bigcarl5000kg]

Here another version of LISP from AutoCAD LISP Forum = my favorite LISP - including checking whether the sphere object already exists = if not, the sphere object will be inserted / whether the position of the center of gravity has changed = the existing sphere object will be moved. Command "astm4balancepoint" implemented - there is no need to do this command separately

(defun C:SACOG ; = Sphere At Center of Gravity
  (/ COG ss sph)
  (command "_astm4balancepoint")
  (setq COG (getpropertyvalue (entlast) "Position")); location of Point
  (if (setq ss (ssget "_X" '((0 . "3DSOLID")))); Sphere already exists in drawing
    (progn ; then -- Move it
      (setq sph (ssname ss 0))
      (command "_.move" sph ""
        "_non" (vlax-get (vlax-ename->vla-object sph) 'Centroid)
        "_non" COG
      ); command
    ); progn
    (command "_.sphere" "_non" COG 30); else -- draw it <---EDIT [radius from 30 dia. Message 1]
  ); if
  (prin1)
)

[bigcarl5000kg]

Use please this version, with additional UCS set to world = prevent the rotation of the sphere's position during insertion, if UCS rotated before:

(defun C:SACOG ; = Sphere At Center of Gravity
  (/ COG ss sph)
  (command "_ucs" "")
  (command "_astm4balancepoint")
  (setq COG (getpropertyvalue (entlast) "Position")); location of Point
  (if (setq ss (ssget "_X" '((0 . "3DSOLID")))); Sphere already exists in drawing
    (progn ; then -- Move it
      (setq sph (ssname ss 0))
      (command "_.move" sph ""
        "_non" (vlax-get (vlax-ename->vla-object sph) 'Centroid)
        "_non" COG
      ); command
    ); progn
    (command "_.sphere" "_non" COG 30); else -- draw it <---EDIT [radius from 30 dia. Message 1]
  ); if
  (prin1)
)

[zirudezirude]

How can you determine the center of gravity of a part of that structure (portion)?

Do you need to create a separate file for that portion? or just turn them of?

[spayne76BBK]

I presume this was never implemented? There is no "model object" that we can select in the drawing style manager?

[bigcarl5000kg]

The command _astm4balancepoint put a 2D point in the balance point of whole model or of selected parts. In the management tools can be activated Detailing of CAD objects in camera drawings. In the drawing styles you have the possibility to use additional ACIS bodies, if these are inserted in the model ( eg. 3D solids). These will likely be the only options available.

[spayne76BBK]

Yikes! No way in hell I'm jumping through that hoop unless it's automated. Boo autodesk! Boo!

[bigcarl5000kg]

Haha, Advance Steel is since 03/2023 in maintenance mode ... no further development