CGTalk - jsForearmSetup

cavetroll

06-26-2003, 08:54 PM

heya all.
I got this radius/ulna setup from Jason`s first dvd implemented in a character. Evereything works very well so far but when skinning those guys I can´t work out how to successfully weight the radius and ulna. I really don´t know how to get a nice deformation out of it. The forearm is getting compressed between those bones and looks really ugly.
I remember that there once was a thread comparing this setup to the second-split-bone-setup in the forearm, dealing with deformation. Also tried influence objects parented to the radius and ulna, but... And I remember that Jason was talking about a "volumetric" skinning system they are using at WETA. Maybe this setup does not work with the maya skinning system??? Maybe I am too stupid right now, but did anybody ever successfully weight this radius/ulna thing using smooth bind? Even the skin at the wrist gets teared apart, because the radius_end does rotate with the wrist, compared to the ulna_end which does just translate with the wrist. Does anybody get me?
Help and suggestions greatly appreciated!
Maybe I should go back to the split-bone-setup?

Cheers, Tom.

cavetroll

06-30-2003, 09:13 PM

sorry for posting a question. :thumbsdow

Phearielord

07-01-2003, 01:51 AM

hey cavetroll

I use the forearm setup in all my characters....it's great.
Though I must admit, it is slightly harder to get the skin weights right across that area.
Just using the 'paint weight tool', I just assign the majority of the weight for the forearm to either of the 2 bones.....not both.
The weight will slowly decrease, shifting to that of my normal forearm bone I use for IK (I have 3 bones in the forearm area).
The area around the wrist will solely be weighted with one bone (the major/leading bone I talked about earlier).
I hope this is clear enough......just smooth the weights out around the forearm....
:)

cavetroll

07-01-2003, 01:59 PM

heya Phearielord.
thanx for answering :thumbsup:

yeah. that´s what I figured out, too. I put nearly all the weights to the "inner" wrist bone, which in my case is called radius_end. the rest goes to the wrist joint to have action in the skin happening when rotating the wrist down or to the side. I also happen to have the third "low_arm"-bone in my forearm.
maybe it just takes longer to paint this stuff, than in the split-forearm-setup. what confuses me the most is that when you paint the weights to the "main"wrist bone (radius_end) the skin rotates differently than when you paint it to a split-forearm (because of the position offset to the wrist joint). my radius_end has the same orientation as the wrist_joint, so this shouldn´t happen. maybe it is because of the ik in the radius bone??
Anyway I need to setup some influence objects to spread the skin apart, to maintain its volume when twisted about my local Y-axis. mmmhhhhh.....
Life is hard sometimes..... mmhhh, sorry.
Also tried a twist deformer in a different setup. Doesn`t work that bad....
Anyway, back to my painting....

Thanx again, take care,
tom.

Phearielord

07-01-2003, 08:11 PM

mmmm.....
I think I'm getting what you're saying...

anyway
hope you get it fixed :)

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