View Full Version : Squash Arms Opposite

03 March 2008, 04:39 PM

I set up a muscle bone and parented the autorig rig to it to squash and stretch my whole character (thanks to ulven on that). What I want to do now is set it up so the arms do the opposite of what the squash bone is doing. Right now when he stretches his arms squash and when he squashes his arms stretch. I tried to make some kind of expression to reverse the upper arm bone squash and stretch from that of the muscle bone but I can't get it.

Anybody have any idea how this might be done?

Here's a movie of the squash and stretch as it is now: (

03 March 2008, 04:53 PM
All I can think of off the top of my head it to use some meta effectors to isolate the arms from the body.. perhaps then if u make separate muscle bonze to scale each arm u can write an expression that links it to what the body squash is doing. Speaking from very little experience with messiah.

03 March 2008, 04:58 PM
The arms are actually doing what they're 'supposed to' from what you're doing. What's happening is that you are squashing him down and the muscle bones are trying to preserve volume by squashing everything out to the sides. If you uncheck X or Y scale in your muscle bone in setup mode, it should stop sqashing like that, but will do so for the entire charcter.
So, as I said before, you're generally better off squashing things locally and seperately, since it gives you more control over what happens with the deformation. This way of squashing the entire character can be useful, and I'm using it in one of the rigs on an advert I'm working on right now, but I think local, seperate squash and stretch is better on bipeds in particular.
If you still want to counter animate the arms squash like this, you can parent each arm to another muscle bone going up, and stretch that when the other one is squashed, either through expressions or through keyframes.

Best of luck

03 March 2008, 05:38 PM
Another solution is to setup completely new bone_deform (below rigs bone_deform) to handle global s&s. Downside is that your actual rig would be off after s&s.

03 March 2008, 01:29 AM

I been messing around with this. I got it to do what I want it to do by making a seperate control for the arms to squash and stretch them. I used expressions to make the upperarms scale like a conrol bone in z and scale the opposite in xy. I think I may mess around with making the spash and stretch locally on the rig now that I have a better idea.

Here's him Squashing:

03 March 2008, 02:40 AM
Could you explain it's application? I'm just wondering why you would want squash and stretch to affect the entire character. I use separate squash and stretch for each limb, spine and head so that I can have control over the arcs and timing, but I'm curious to learn other people's approach.

03 March 2008, 03:01 AM
This is just for an animation where the frog is squashed from a heavy object from above and then pops up from under the object.

I started it in max but was having trouble with dropping the object and stuff. I found a great rig for max here on cgtalk though. But am now giving this animation a shot in messiah.

Here's what I had in max:

03 March 2008, 08:37 AM
you might want to play with melt for this kind f effect. You can make the effect thicker and control the spread, making him pancake and then pop back up at will.

03 March 2008, 09:57 AM
I rigged a character that had to Strech and Squash limb independent and all together also, so it could be scaled to fit a Scene or simply because it needed to be Streched and Squashed as a whole(not done in messiah), you need to add the Scale of a Parent Null or whatever Parent objects into the equation with Expressions, this will prevent the overstrech you are getting...

How is this done in messiah? It has passed too many winters since the last time I wrote an expression in messiah for me to remember the exact syntax, but im sure someone more tech gifted will help ya out :D

You can also use the Melt like already told, its cool for simple stuff like this or you can do it with Morphs, takes more time but it can be done.. of course a Lattice would also be PERFECT ;)

03 March 2008, 06:04 PM
Thanks, melt is pretty handy. I have results that will work with the animation with a combo of squash and stretch and melt.

Complex expressions are kinda over my head at the moment so not sure how I could fix up all the scale of everything. I think this will suffice for my purposes though.

Here he is:

Thanks folks.

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