how do I link to IK joints to work together in MAX?

[thomas7g]

Hey everyone! I am trying to get this arm mesh together for a job. But I am having problems.


I have this so far:

http://thomas7g.3dgladiators.net/posted/fingertest.jpg

But I have to add these pistons on the bottom that move the finger joints. The finger links work. I got the pistons connected at the base. The extending of the piston rod works. But how do I connect it to the finger since a child link can only have one parent?

here is a test of the problem I am working out. The "finger" and the piston are anchored on one end to the same helper dummy point. But the finger and piston are attached to different helpers on the other end.

This unit will hinge to other finger links on each end.

http://thomas7g.3dgladiators.net/posted/problem.jpg

Does anyone know how to do this? I don't need a long answer. I just need a big clue. :)

[TheHobb]

Well, I don't know max at all and ik chains are the thing I think I have the absolute least amount of experience dealing with but here's a possibility...

Can you parent the big part of the piston to the dummy point or something constrained to it?

And can you parent the small part of the piston to the finger or the joint at the other end?

And then can you make the big part of the piston look at the small part of the piston and vice versa so they are looking at each other?

This way you set up an IK cheat that actually is simple look-at functions and parenting.

[thomas7g]

If I understand it right, I can't do it. Its the second step that's the problem.

And can you parent the small part of the piston to the finger or the joint at the other end?

When I try to parent the small part of the piston to anything that already has a parent, it breaks the first parent-child link. A child cannot have two parents. At least not in max r3. :(

But thanks for at least looking. I appreciate it.

Anyone else know links?

[TheHobb]

I'm not sure I understand the problem. A parent can have multiple children right?

The small piston would be a child of the finger, not it's parent. The piston would have no other parents and adding a child to another object should be no problem.

[Ashrak]

have you tried to use a dummy as the parent and then next in line would be the large piece and then the others??

[thomas7g]

Tried that Ashrak.:(

Hobb- yup a parent can have multiple children.

The problem is the piston has to be anchored at both ends. Its like a hydraulic piston that moves the next lower joint of the finger. If you look in the render of the actual pieces the piston (in red) Will go from the center of the long middle joint, and the tip of the next finger piece.

You can easily parent the piston. But you can't attach it at the bottom(right) because every piece already has a parent link. And if can't give a piece two parents. And I tried grouping the dummy children, but it won't group them if the are related farther up the hierarchy. The grouping option is greyed out.

[thomas7g]

Am I being unclear as to what the problem is?

:confused:

The piston comes directly out of the first finger piece and then should connect to the next finger piece. Its the last connection that's the problem.

[TheHobb]

What I'm talking about is that the the two parts of the piston does NOT have to be parented at both ends because you need to seperate them. The piston is made of two parts, a thick tube and a thin tube. You only parent one end of each part and let the other end be fly free as it is constrained by a look-at function (like you would put on a light or a camera to keep looking at an object).


Dummy Parent (parent) <--- Big Piston Tube (child) ->lookat<- Small Piston Tube (child) ---> Finger/Dummy Child (parent)

The two parts of the piston are no longer parented/connected to each other and instead simply look at each other.

[Darrell Lawrence]

Try this:

Big piece is the Dummy Parent.

Piston should be TWO pieces: large end of it and small end of it.

Child to the Dummy Parent.

Fingers child to the small piston piece.

Then when you move the piston pieces, the IK affects everything connected to them, parent or child.

[thomas7g]

problem is the piece you are trying to parent to is already parented to someone else. And that breaks the connection.

I think I have a clue. There must be some way to bind two helpers together. But I'm haviong problems with it. :(

[thomas7g]

WOOOO! I figured it out. It is BIND to object. My link works!!!!

Thank you EVERYONE! I really appreciate the help!!!!