Adding a Relation to a Point

[LouR]

I wonder if someone can help me out with this. I added a "point" to the
"Center of Gravity" in
my "assembly". as i work and add parts etc to my assembly i would like to
have this "point" i
added changed as the "center of gravity" changes. I like to make a relation
between this "point"
and the "center of gravity", anybody know how to do this??

thanks

LouR

[GWDavis28]

Lou, don't use a point use a coordinate system. Then assemble the CG part to the CSYS and then create an analysis feature that will update the CSYS to the latest CG information. CG is one of the options in the analysis feature, you need to dig kind of deep.

Hope this helps, Glenn |B)

[LouR]

Glenn thanks for the information. I needed the point on the CG to show its
location in 2D so i could dimenion it.
but thanks again for your help.

LouR
=============
"GWDavis28" <Glenn_W_Davis@Raytheon-dot-com.no-spam.invalid> wrote in
message news:SMidnXv3Du92oUjfRVn_vg@giganews.com...

Lou, don't use a point use a coordinate system. Then assemble the CG
part to the CSYS and then create an analysis feature that will update
the CSYS to the latest CG information. CG is one of the options in
the analysis feature, you need to dig kind of deep.

Hope this helps, Glenn |B)

[Gary Miglionico]

Lou, First you need to calculate mass properties using >edit >setup

mass_prop. In the dialog box, the
'source' should be set to 'Geometry and parameters' , then click

on >generate report.

Next, create a coordinate system using the default csys as
reference, then create a relation in the assy with the three
dim's which referenced the csys. It should look something like this:

d66=mp_cg_x ("","ASM_DEF_CSYS","")
d67=mp_cg_y ("","ASM_DEF_CSYS","")
d68=mp_cg_z ("","ASM_DEF_CSYS","")

When you regen the model the new coord sys will update. Each time
you change the model you need to recalculate the mass prop using the
generate report as above. Then a regen should update the coord sys., you can
add a point to the new coord sys if you need a point. This seems like alot
but a couple of mapkeys and your done quickly.
Goodluck,

Gary Miglionico

"LouR" <russo1@bnl.gov> wrote in message news:db0jqq$hem$1@news.bnl.gov...

I wonder if someone can help me out with this. I added a "point" to the
"Center of Gravity" in
my "assembly". as i work and add parts etc to my assembly i would like to
have this "point" i
added changed as the "center of gravity" changes. I like to make a
relation
between this "point"
and the "center of gravity", anybody know how to do this??

thanks

LouR

[David Janes]

"Gary Miglionico" <garymig@bnl.gov> wrote in message
news:db3llg$fkk$1@news.bnl.gov...
Lou, First you need to calculate mass properties using >edit >setup
mass_prop. In the dialog box, the
'source' should be set to 'Geometry and parameters' , then click
on >generate report.

Next, create a coordinate system using the default csys as
reference, then create a relation in the assy with the three
dim's which referenced the csys. It should look something like this:

d66=mp_cg_x ("","ASM_DEF_CSYS","")
d67=mp_cg_y ("","ASM_DEF_CSYS","")
d68=mp_cg_z ("","ASM_DEF_CSYS","")

When you regen the model the new coord sys will update. Each time
you change the model you need to recalculate the mass prop using the
generate report as above. Then a regen should update the coord sys., you can
add a point to the new coord sys if you need a point. This seems like alot
but a couple of mapkeys and your done quickly.

You're right, this is the classic approach to representing, in a more permanent
way, the center of mass in a model/assembly. And it works, but not very well.
Without some trickery on the user's part, it is always representing the COG as it
was with the previous part added, not the latest.

Here's why: adding a part causes a regen which moves the CSYS (or point) to the last (previous) position calculated by Generate Report. Now, you actually need to regen, again, but nothing happens automatically. You have to remember to do it. And if you don't, the position is NOT updated.

And, it is completely ineffective in part mode. There you add or subtract a feature; part COG does changes to the value calculated last by Generate Report. But after that, there is NO FORCED REGENERATE to get it up to the value of the latest Mass Prop. That's one reason they dumped the form embodied in the relation d66=mp_cg_x ("","ASM_DEF_CSYS","") and went to PRO_MP_CGX because it would automatically update without the manual 'Generate Report'. This is available in later revs of Pro/e, from about Wildfire on. BUT, the best of all possible worlds, I repeat, is the Analysis Feature. You have to buy Behavioral Modelling to get it, but you'll be a better person for it.

David Janes