Hi guys,

I've been making animations in Poser for a while now (to create new units for Civilization III) and I've hit a problem.

I want to make some animations where the character is wielding a weapon or tool with two hands. For example, using a pick, thrusting a pike, or doing some digging. Now clearly this is harder to do than with a one-handed implement. To make the character wave a one-handed sword about, you need only put the sword in his hand, parent it, and then move his arm about. But with a two-handed sword he needs to keep both hands on the sword at all times. Ideally, I need to be able to parent the weapon to both hands at once. Or, even better, I need to parent it to one hand and then parent the other hand to the weapon.

As it is, I have to treat the prop like a one-handed prop by parenting it to the right hand and moving that. Then I have the extremely tedious task of manually moving his other hand, frame by frame, so that it looks like it's holding onto the prop all the time. This is not only tedious but hard: it is very easy to move the right arm/prop combination in a way that is actually physically impossible for him to get his left hand onto it properly.

The ideal, ideal solution would be to parent the prop to both hands and switch on IK chains for both arms, with the prop as the final element. Then I could just move the prop and his hands would remain glued to it, so he would move his arms in the proper way. Think how easy it would be to do (say) a mining action with a pickaxe this way. And think how difficult it is to make that action using the move-one-hand-manually method described above!

So is anything like this possible? Can I somehow parent a prop to two hands, or at least mimic such a thing? Any advice would be massively appreciated.

The key is to think backwards.  

In real life, of course, the brain gives signals to the muscles 
which move the pickaxe.

In Poser life, think of the pickaxe as the intelligent element,
which knows how to perform its particular moves.

Move it through the proper cycle, then take both hands 
(with IK on) and parent them to the pickaxe, so that the tool 
is the parent and the hands are the children.

(Maybe this isn't -quite- backwards after all...  when you get
accustomed to using a tool, it feels like the tool is in charge 
of the movement, and the brain is just sort of monitoring.)

Search "baseball bat parent" with 0 - 700 days as your range, Poser as your forum, and Ockham as your user, and you will get a bunch of discussions of the solution. Be warned, my impression is that P7 has screwed up the old parenting code somehow. I just tried Ockham's directions and I crashed P7. I restarted and tried again, and it worked the second time. i have had it not work in the past.

Quick version:

1. Position object and hands for first frame.
2. Turn on IK for both hands. If you don't, you can't parent them.
3. Parent each hand to the object.
4. Move the object to create new frames.

Steps 1 and 2 are interchangeable; you can turn IK on and off as you pose the first frame. The important thing is that IK must be on when you are parenting the hands, or Change Parent will be grayed out.

You can adjust the hands for rotation, grip, and so forth in key frames. Do not turn off IK, no matter how tempted. If you do, the parent relationship is immediately cancelled for the entire animation, and the next time you run it, the movements will be completely different.

I did this as I described it, so I'm pretty confident that it will work.

M

Oops. What he said. (cross post) ;)
M

Thank you both enormously. I was convinced that this should be possible, but the one thing I didn't know was:

Quote - 2. Turn on IK for both hands. If you don't, you can't parent them.

I wanted to parent the hands to the prop, but saw "Change Parent" greyed out so it seemed completely impossible. I didn't know that turning the IK chains on first would change this.

Everything seems much easier now. I'm using Poser 6 so hopefully that crashing won't happen (although I'm used to it by now, if it does...). Thanks again!

Re P7 crash:  That's interesting, and worth watching for.  I haven't had
a crash when doing this sort of procedure ...  Yet!

Maybe it's because I don't use the newer figures, some of which have
complex IK setups.   I just use good old Kona, seen in my avatar, and Posette.

My last crash was with the old stick man, so I don't think it was related to the figure. P7 has some serious stability problems. I'm about ready to transfer back to P6. Just have to make sure my G2's will work there.

M

Yup, P7 is amazingly fragile.   Seems to have reached some
kind of "juggler's limit" with the original code, the various room
modules, and the newer WxPython overlay.  

Give it any sort of distraction and it drops all the dishes.

Quote - Give it any sort of distraction and it drops all the dishes.

As someone said elsewhere, "Well put." My office is awash in broken dishes....

M