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View Full Version : Fish Rigging - Spine/Fins Setup


danethomas
05-12-2008, 02:59 AM
I've had a good look through the forums and probably the best fish rigging thread is this one (http://forums.cgsociety.org/showthread.php?f=54&t=410801&highlight=fish)- especially Pen and Eek's discussions further down the thread and Pen's post here (http://forums.cgsociety.org/showpost.php?p=3892314&postcount=7) complete with his more technical write up on his site here for his Frank The Fish (http://paulneale.com/technical/FrankFish/frankFish.htm).

The problem is that I'm setting up my Characters in Maya. Granted a lot of the information is cross platform, I was just wondering if I could have some light shed on some of the (in my mind) complex issues faces with a (seemingly) simple fish rig.

I'm also interested in procedures that may have not been so easy back in 2006 when Pen did that write up - ie. Maya's new cloth.

Basically, the rig is for a stylized fish character (think Nemoish) that I think should have some sort of 'auto swim' mode as well as keyframe-able controls to hit the required poses and additional deformations. It's a hero character so will require a full facial setup but I'm fairly comfortable in setting that up.

What would people recommend the best setup is going to be? A series of splineIK's, one for the spine and then a couple in the tailfin mixed with a series of seperate bone chains for the main fins.

I've had a look at Aaron Holly's Fahrenheit Digital DVD and looked at the ribbon spine setup which seems to have all the flexability and control that would be required without having some of the downsides of the splineIK setup.

From what I have read most people have used an offset sine curve to control the movement in the fins. The applitude of this could be set to a control that looks after the speed of the fine. Should these fins be a 4-5 bone structure with the sine curve and soft bodies or should I be looking at cloth for these fins.

As I understand it, if I do use cloth and set it up correctly I could achieve the wave like motion of the fine when the fish is 'moving' but I would have to rely on forces when the fish stops. If thats the case I'm not sure if I'm sacrificing too much control as well as introducing a world of pain when I start to animate things (ie. forces on off when the fish starts/stops while still getting it to look uniform and fluid). I'm also looking at a simple way to blend the auto swim with my keyframed animation as surely no one animated a fish's fins manually.

There are very few fish rig tutorials online and initially a fish rigs seems like it would be fairly simple (at least in my relatively basic rigging knowledge) but when you start writing down the requirement and incorporating 'auto swim' and additional poseable controls then it starts to get fairly complex.

I'd appreciate any info that anyone might have to tackle this rig. This is for a major Work project due towards the end of the year but I'm just starting my rigging research and getting into production now.

I haven't had a whole ot of experience with rigging and production setups but am doing a ton of training material and slowly getting up to speed - with this in mind it would be appreciated if any answers could be (atleast initially) pithed at an intermediate level.

So if you find you are writing stuff like


V(q1..qn) ~ 1/2(E(omega^2*V/omega*q1*omega*qj)q0 n1*nj


Maybe knock it back a level (unless you have put it in step by step) ;)

I'd love to keep this thread going with both feedback and input throughout my production so I can get this rig working just right.

PEN
05-12-2008, 11:13 AM
I"m glad that you like Frank. I have to tell you though he was way more complex then need be for what the end product needed. When the piece started out Frank was seen sitting on the couch and doing other things that required a spline IK setup. If I were to do him again I would two with two FK chains. One that has all the auto swim system built in and I would just use sin for that with a series of spinners to control the different offsets, amplitude and period. The second set would be for shaping the fish and used by the animator. This way you could have the swim action working on it's own and shape the fish as needed.

I haven't use Mayas new cloth, it does look fantastic how ever, but I'm thinking that it is over kill for this sort of thing. I would think that some good rigging practices would be better suited.

danethomas
05-12-2008, 11:22 PM
Thanks for the reply.

So I'm looking at 2 FK spines - one for auto swim and one for animation control/movement. Regarding the blending of the two FK's would I need to incorporate weights for each of the FK spines or with one of them being the autoswim the second one will just allow me to set my poses while having a (keyframable) swim/wiggle going the whole time.

Regarding the fins did you use a max equivalent of cloth for them (ie. in this video http://paulneale.com/temp/fishFin.mov) or is that going to just be another offset sin wave with soft bodies.

I've started putting together a test spine rig and have the sine wave and offset looking fairly good - with a speed/amplitude control as well as an on/off switch.

I've always wanted to keep this an expression driven rig rather than getting too bogged down with cloth so I agree with you there.

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05-12-2008, 11:22 PM
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