(maya) probably a noob question on rigging

5jay5

I have a problem with the IKFK arm i am building in maya. The upper arm twist joints, the last segment does a 180 whenever I move the forearm past 90 degrees. The upper arm twist is made of 4 joints, with the first and last attached to a EP curve, skin bind with a shoulderbind_R and elbowbind_R joint parent constrain to the result_upperarm_R and result_forearm_R joint to control the twist. The problem seems to be the elbowbind gimbal locks at 90 degrees, adding 180 degrees to the x and z axis. I just cant figure out how to fix this make this work properly. This happens for the shoulder and wrist as well.

oglu

I cant help you with this issue. 

But if you just need a rig dont do it yourself. Use an autorigger like mGear. Noone does create rigs by hand. 

If you like to learn rigging start with easier stuff to get the basics. 

Alex_J

i not rig expert but I believe you'll need an aim constraint on the elbow. Also try tweaking its position slightly to influence which way it wants to bend.

Like oglu said, for human characters there is so many powerful and free auto-rigs out there, no reason to do yourself unless you just triyng to learn (in which case, follow a tutorial and get a mentor). rigging is too complicated to trial and error alone.

HumanIK is solid for human characters. I also used advanced skeleton which is very robust and versatile for all types of rigs. Pluralsight has a couple rig tutorials that will show you how to make aim contraint for proper bending elbows and knees.

jRocket

It might be a rotation order issue on the bones. Try changing the rotation order to one of the other ones.

5jay5

I tried the rotation order on the segment joints, the result joints, and everything else attach to this part of the rig including the constrains with no effect. Aim constraint works but doesn't, it appears to fix it however the segment joints and their bind joints no longer stay with result joints and adding a point constrain on top is the same as a parent constraint. I was following a 2014 rigging tutorial by Maya Learning Channel on YouTube, looking back at the videos his rig has the same problem. Ill either leave it as is and add a switch or something to turn the twist joints manually when going past 90 or some convoluted method using multidivde nodes run by an X axis to automatically run the thing like an Ik spline handle. Anyways thanks for trying to help in the future ill probably use a auto-rigger, I just want to know how rigs work so i can add features to them later.

oglu

Take a look at mGear its a modular system and you can add features as many as you like.
Its to complex to learn to crate such rigs. They use custom solver and a lot of python magic.
mGear is free and super fast and easy to learn.

If you dont try to become a rigger i wont try to learn it. It does take years to master like anything else.

mGear + Brave Rabbits smoothTools 
http://www.braverabbit.com/brsmoothweights/

https://youtu.be/tFWyAd5-__0

5jay5

Thank you oglu for mGear + Brave Rabbits smoothTools