not intersecting parts in inventor

[greencactus3]

i did find this while searching but im not sure if thats exaclty what i want..
http://www.chiefdelphi.com/forums/sh...n+c onstraint

well, im doing a large multipiece project and some parts are ball cups with balls. kinda like a ball and socket... and some of these tend to flip around so the cup wall intersects with the ball end screw.... i dont want this. yes i can manually adjust each and every one so they wont, but every time i have the assembly move, a couple of them spin and stuff so they have intersecting points.

is there a way to keep them from doing that? kinda like a motion limit constraint?

[Greg Needel]

any way you could post a screen shot of what you are talking about. I think this will help us understand a bit better what you are talking about.

[Madison]

Does Inventor allow you to constrain movement with physical dynamics? If it doesn't by now, it should.

In Solidworks, I can move a piece freely or choose to move it with physical constraints enabled such that the parts interact with one another as true solids and will stop at collisions.

[petek]

Should the ball stay in the same position and orientation in the cup, or do you need it to move? You probably are using a tangent constraint, but that will not keep it from flipping out, so you might have to constrain some other features or planes (like the Origin planes or axes).

Doing that will limit (or prevent) motion, though. Usually not a problem for static designs, but might keep you from running constraint-driven animation.

Like Greg suggests, a picture would be helpful.

[greencactus3]

Originally Posted by petek

Should the ball stay in the same position and orientation in the cup, or do you need it to move? You probably are using a tangent constraint, but that will not keep it from flipping out, so you might have to constrain some other features or planes (like the Origin planes or axes).

Doing that will limit (or prevent) motion, though. Usually not a problem for static designs, but might keep you from running constraint-driven animation.

Like Greg suggests, a picture would be helpful.

sorry i dont have inventor 10 at home and cant open the project but if theres no snowday tomorrow(which i hope there will be) ill try to remembr to take a screen shot.
so well... what i have now ill post. thumbnails. well the ballcup end and ballend are constrainted with the center of each sphere portion. so well the cup cups over the ball and the center of the cup sphere and center of the ball sphere are always at the same point. allowing me to have it move. which is needed for allowing my suspension and steering parts to function. no idea if you can see the assembly i have backed up in that thumbnail.... well i guess i suck at explaining in words and will need to get a better screenshot than that lol

[greencactus3]

okay i got a screenshot. i circled in green how these ballcups should be over the balls. in red i circled where they are constrainted with the center of the spherical parts, but the "wall" of the cups are intersecting with the "ball" or the screw. anyone know how to keep them from doing this?

[petek]

I would do it with a tangent constraint between the ball and socket surfaces and an anglular constraint between planes or axes on the ball and the socket. I played around with a ball joint model last night and found this to work as long as you don't need more than one degree of freedom (motion, as in constraint-driven animation). When I tried to allow rotation around the ball and yaw side-to-side, it would usually flip orientation at some point.

[SpaceOsc]

i believe inventor (8-10) has a function for solid parts to give them material and mass that cannot be penetrated into. it might be along the lines of "Contact Surfaces" or "Contact Set" where u would have to select which parts cant penetrate each other and instead push and pull on them if there are degrees of freedom. if i find it ill post. but im sure another inventor user knows what im talking about

[greencactus3]

Originally Posted by petek

I would do it with a tangent constraint between the ball and socket surfaces and an anglular constraint between planes or axes on the ball and the socket. I played around with a ball joint model last night and found this to work as long as you don't need more than one degree of freedom (motion, as in constraint-driven animation). When I tried to allow rotation around the ball and yaw side-to-side, it would usually flip orientation at some point.

yea. all the cups move in more than one axis so the angular wont work. thanks tho....which is kinda why its a ball and socket joint..

SpaceOsc- i sure hoope you find that for me soon!!

[greencactus3]

anyone figure out a good plan yet?