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Cable rig - fixed connection at both ends?

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I am kind of stuck on this. I can't quite figure it out.

 

I have a cable connected to the base of the head of my terminator model and it needs to be flexible with a chain of bones and connected to the bottom of the neck/top of the chest at the other end. How would I go about setting this up? It is a flexible cable... but a little stiff. It isn't limp. To create the "stiffness" I'm only using 3 bones in the chain... this keeps the cable from flexing too much... but I still need to keep both ends locked to different bones or parts of the skeleton that move independently.

 

I started out with a single chain coming down from the top at the base of the head. the last bone in the chain has a translate constraint to a bone at the bottom of the neck... unfortunately this doesn't work, the last bone still "disconnects" from that base. The constraint doesn't really keep it in place. I was hoping this bone would stay in place and force the other bones to bend to follow along.

 

Look forward to hearing any ideas while I continue to play around with this.

 

-vern

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I am kind of stuck on this. I can't quite figure it out.

 

I have a cable connected to the base of the head of my terminator model and it needs to be flexible with a chain of bones and connected to the bottom of the neck/top of the chest at the other end. How would I go about setting this up? It is a flexible cable... but a little stiff. It isn't limp. To create the "stiffness" I'm only using 3 bones in the chain... this keeps the cable from flexing too much... but I still need to keep both ends locked to different bones or parts of the skeleton that move independently.

 

I started out with a single chain coming down from the top at the base of the head. the last bone in the chain has a translate constraint to a bone at the bottom of the neck... unfortunately this doesn't work, the last bone still "disconnects" from that base. The constraint doesn't really keep it in place. I was hoping this bone would stay in place and force the other bones to bend to follow along.

 

Look forward to hearing any ideas while I continue to play around with this.

 

-vern

 

 

I think this has what you want... I don't completely remember how I did it -- sorry. Done a long time ago. Put model in an action and use pose sliders to make it move... watch the two things that do what you want. Look at how I built it. Need help, I'll try to help.

 

Hope this helps!

Rusty

 

MechanicalAlienClaw010.zip

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I haven't looked at any of the above solutions, so forgive me that- I would approach this on a simpler level...by just using 'weights' and varying the amount of influence from part to part.

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A kinematic constraint is what will keep the end of the chain tracking the body part. Just apply the constraint to the last bone in the chain and target it to the body part it is supposed to attach to.

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Thanks for the help guys!

 

I discovered the kinematic constraint late last night. In all the years of using AM I don't think I ever used a kinematic constraint.

 

I am going to study these other solutions. One problem that arises with the kinematic constraint is that the cable doesn't move in an orderly way. It will bend and kink at weird angles poking into the neck. It is different every time. If I put the head back into the original position the cable/hose is in a new awkward position. I need to control it so it only bends in a specific way. I still need to lock it down though on each end.

 

I could just animate each bone of the cable... but I want this to be as "automatic" as possible. There is really a limited range of motion for the cable. It should flex but just a little bit and it should return to it's original position. Right now it gets all twisted and pokes out funny.

 

What I really want is a kind of "spring" rig. The hose or cable maintains its shape relative to the neck in the default pose but can stretch and bend slightly as the head and body move and twist.

 

-vern

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One problem that arises with the kinematic constraint is that the cable doesn't move in an orderly way. It will bend and kink at weird angles poking into the neck. It is different every time.

 

Use an aimat constraint on the middel links to make then tend to some target. Much like the knee targert on leg rigs (also a kinematic constraint situation) does.

 

http://www.hash.com/forums/index.php?s=&am...ost&p=43005

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After playing with some options I've decided to go with a really simple solution.

 

The tubing or cable in my example has a slight curve conforming to the shape around the neck. I am using one long bone that is a child of the head that starts at the base of the cable at the base of the head and ends where it connects to the bottom of the neck.

 

This one long bone has an aim at constraint with scale to reach z axis only to a bone at the base of the neck. It works perfectly. The slight scaling distortion is hardly noticeable. The cable maintains its shape, stretches only slightly and doesn't bump through other parts of the neck.

 

If I have any other issues I can always tweak with smart skin.

 

 

The position of the cable in this render is incorrect. I hadn't constrained it yet.

headtest1.jpg

 

-vern

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