rotation linking in 3dsmax (solved)

Rankenphile

so I'm working on a robot arm/hand for a school project, and I want to know how to link objects to share a trait, such as rotation.

For example:



I've got the three joints on the "finger" of the hand, marked A, B and C. If I rotate Joint A, I want Joint B and Joint C to rotate as well, effectively closing the hand, without me having to go in and control each and every joint - I want it to be automatic.

And I can't fucking figure it out to save my life.

Any help?

wallabeeX

If you were in Maya, there'd be several ways to do this. One would be writing an expression, and the other would be setting a driven key.

There's definitely a way to do both of these in 3d Studio Max. I don't know MAX script, but it's likely something like:

jointB.rotateX = jointA.rotateX
jointC.rotateX = jointB.rotateX

Very simple script. Gotta be a way to do it.

Take it to CGtalk.

Defender

Check out the Comet charRigger script. It has a feature on the hand that actually does one better! It has a bunch of custom values that you can key that control stuff like the spread of fingers, and open/close of course. There are other neat things in the rig like ankle pointing, which is great for transferring weight from heel to toe during walk cycles, and knee/elbow direction, which helps to take out some wonk from arm/leg anims.

I've never scripted a feature like that myself, but this rig is pretty solid.

http://www.comet-cartoons.com/maxscript.php

I would also say to check CGTalk/ScriptSpot. I'll see if I can give a better answer.

NotYou

You can either just link them if you want it to share rotation and position. It's one of the tools that's in the tray at the top. Or you can use constraints, which are in the animation menu at the top.

Frosty

I think what youre looking for are Wire Parameters, where you can "wire" changes from one object to affect another. Youll want to wire each finger bone to follow the rotation of its "parent", though probably not on a 1-to-1 ratio. That way you can just rotate the bone closest to the palm of the hand on each finger and the rest of the finger will curl with it (which is what you want if I'm reading correctly)

If you just link them, the finger will remain straight when you move the first bone, and youd have to rotate each bone seperately if you wanted the finger to curl

Rankenphile

Frosty wrote: »

I think what youre looking for are Wire Parameters, where you can "wire" changes from one object to affect another. Youll want to wire each finger bone to follow the rotation of its "parent", though probably not on a 1-to-1 ratio. That way you can just rotate the bone closest to the palm of the hand on each finger and the rest of the finger will curl with it (which is what you want if I'm reading correctly)

If you just link them, the finger will remain straight when you move the first bone, and youd have to rotate each bone seperately if you wanted the finger to curl

that's precisely the problem, I've been linking them but having to animate them seperately

I'll look into the wire parameters.

thanks.

Frosty

Rankenphile wrote: »

Frosty wrote: »

I think what youre looking for are Wire Parameters, where you can "wire" changes from one object to affect another. Youll want to wire each finger bone to follow the rotation of its "parent", though probably not on a 1-to-1 ratio. That way you can just rotate the bone closest to the palm of the hand on each finger and the rest of the finger will curl with it (which is what you want if I'm reading correctly)

If you just link them, the finger will remain straight when you move the first bone, and youd have to rotate each bone seperately if you wanted the finger to curl

that's precisely the problem, I've been linking them but having to animate them seperately

I'll look into the wire parameters.

thanks.

FYI you'll still need to link them (I'm assuming each bone is a seperate object) so that theyll stay together

Rankenphile

not using bones, haven't gotten that far in class yet

using object links, and yeah, they're linked to allow them to move with each other

this is one I did last week, btw

http://www.youtube.com/watch?v=fONg0y9FfEI

as far as the wire parameters go, I'm having a hard time understanding how to get them to work - so far nothing seems to affect anything

Frosty

Hang on I'll whip up a quick example with some pictures

Rankenphile

I got it figured out, there were a number of other issues going on with the pieces that were preventing me from doing what I needed, from all of my blind mucking about trying to get it working.

Thanks, guys.

Frosty

Right click on bone1 and go to Wire Properties. Then follow the windows down to the rotation you want (in my case it was the X axis). A little connector line will appear and you want to choose bone2. The same windows will appear so choose Transform > Rotation > X Rotation again.



The parameter window will pop up, and since you want bone1 to control bone2, click the appropriate arrow and then Connect. Note the expression on the bottom right, which by default is just 'X_Rotation', or 1-to-1. You may want to change this to something else like (X_Rotation * 1.5) or whatever works for you.



Then just do the same wiring from bone2 to bone3 and you should be set

edit: damn yooouuuu

Rankenphile

bwahahaha

what timing

thanks, man, I appreciate the effort. I ended up getting the thing working great, and even figured out how to link the control for the parts up to sliders to make my life a hell of a lot easier. I ended up working with one of my professors on it for a few hours.

valeryce

You're a digipen student aren't you?

The answer is in the wire parameters. I got beaten to the punch by frosty, but that's basically what you need to do. If you have any 3Ds questions feel free to PM me, or ask one of us upperclassman on campus.