Center of MASS

This has been requested previously and there is an outstanding Enhancement Request ( 85863 ) mentioned in this thread

communities.bentley.com/.../108297
CR number: 295341

oh good, it was requested 7 years ago. Any chance it gets implemented before the decade is over? :P

doesnt look like it any time  soon, ..didnt   we discuss  a solution for this before .. oh well for those who  are new to the  post and have similar  problem and for the  poster

I think you can do it by combination of  Cad and first principles ..( forgive me  if I'm teaching  grandma to suck physics ok)

Bare with me as  I try to recall how to solve this from college applied Mech class back in the 80's

So ustn can show you the COG or CoM for each part  so  lets call those CG1 and  CG2 , you can connect these two points even though the model is  3d...

Lets call this Total  distance L  now  both  CGs act at the ends  in the same  direction   so sum of the  moments down = reaction up

down M1gx +M2gy = g(M1+M2)(L)  up .. ( about the  real CoG for equilibrium..).

 now the ratio of (M1 to M2) / M1+M2 will be the ration  of (x to y)/L so you should be able  to solve  x and y  by the  mass ratios to the distance.. you  now  now relative to  either end  where  x or y will be  and  what fraction of L , now  where the CGs is known, and the L is known so the ratio of  the masses will tell you where the  real CG acts at along L... that seems right to me but  its been 30 years ....

doesnt look like it any time  soon, ..didnt   we discuss  a solution for this before .. oh well for those who  are new to the  post and have similar  problem and for the  poster

I think you can do it by combination of  Cad and first principles ..( forgive me  if I'm teaching  grandma to suck physics ok)

Bare with me as  I try to recall how to solve this from college applied Mech class back in the 80's

So ustn can show you the COG or CoM for each part  so  lets call those CG1 and  CG2 , you can connect these two points even though the model is  3d...

Lets call this Total  distance L  now  both  CGs act at the ends  in the same  direction   so sum of the  moments down = reaction up

down M1gx +M2gy = g(M1+M2)(L)  up .. ( about the  real CoG for equilibrium..).

 now the ratio of (M1 to M2) / M1+M2 will be the ration  of (x to y)/L so you should be able  to solve  x and y  by the  mass ratios to the distance.. you  now  now relative to  either end  where  x or y will be  and  what fraction of L , now  where the CGs is known, and the L is known so the ratio of  the masses will tell you where the  real CG acts at along L... that seems right to me but  its been 30 years ....

thanks, i'm aware of the math required to do this. The idea is to have the software do this so that don't have to perform this calculation on a bunch of different assemblies or if that geometry changes, having to update where the center of mass is.

we have the ability to store data in the cad file to add "intelligence" lets get this incorporated.

A long time ago, in a galaxy far far away, there use to be a program called Bentley Modeller. This tool had the ability define the CoM. Sadly this was removed, but you can see the CoM in the measure tools

Unknown said:

thanks, i'm aware of the math required to do this. The idea is to have the software do this so that don't have to perform this calculation on a bunch of different assemblies or if that geometry changes, having to update where the center of mass is.

we have the ability to store data in the cad file to add "intelligence" lets get this incorporated.

Yep I knew you knew... but  for others  just  put it in there... plus it was fun to reminisce my  college days... sniff....

Its never  going to get in there in any SS or V8i  current builds as its now all about connect edition...

You might be able to do some clever stuff in CE is tables and links or Fields .. properties...

did you put it into the suggestions for what we need in connect future edition(s)

hope its in there before we retire...! (I'm not using  CE so not sure if can do what you actually  want)

Too bad it was removed from the old modeler...