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Rigging Tips and Tricks : Variable FK rigging with Mentor Jeff Brodsky

Trunk rig – Variable FK – How it works with Mentor Jeff Brodsky, Character Technical Director at Disney Feature Animation

Variable FK rigging with Mentor Jeff Brodsky

A few weeks ago we came across this very cool trunk rigging demo from Jeff and so we asked Jeff to do a making of video and to become a Mentor with us and he agreed to do both!  We are very excited to get to share his skill and experience with all of you and we hope you enjoy this latest #rigtip and give it a try.  Jeff will be working with apprentice students to help them grow and improve their work to be animated feature film ready.

Jeff Brodsky’s trunk rig demo from Jeff Brodsky on Vimeo.

Begin Guest post:

Jeff Brodsky, Character Technical Director at Disney Feature Animation

“Hi, my name is Jeff Brodsky. I’m a Character Technical Director at Disney Feature Animation in Burbank CA where I recently finished up on the Mickey short “Get a Horse” and am currently working on the upcoming movie “Big Hero 6“.

I’ve always been interested in art, movies and special effects. I used to love watching the Movie Magic shows on the Discovery Channel… that was back in the glory days of CG with “Terminator 2” and “The Abyss”.

In 1996 I got a brochure in the mail from the Art Institute advertising their new computer animation program and I thought “holy crap I can learn this stuff!?”. Then I went for a tour of the school and they showed me “the SGI room”. This was a glass room with about 20 Silicon Graphics machines… the same machines I saw on Movie Magic. The tour guide was like “these are the same computers they used on Jurassic Park and Twister” and at that point I was sold. 🙂

I graduated in 2000 and since then I’ve moved all over the country spending most of my time at Disney and Blue Sky (where I worked on Epic, Rio, Ice Age 3 & 4 and Horton Hears a Who). I gotta say the rigging team at Blue Sky is one of the most creative, talented group of badasses I’ve ever had the pleasure of working with. That’s where I learned most of my technical chops.

My favorite aspect of rigging is that everyday is a new challenge, a new puzzle to solve and it forces us riggers to use our noggins for something more than watching Breaking Bad 🙂

The Variable FK rig was one of the tougher challenges I’ve overcome. The animators wanted elephant trunk rig that was iPod simple but with complex behavior. This is what I came up with – Enjoy!”

Trunk rig – Variable FK – How it works from Jeff Brodsky on Vimeo.


Q: smann

awesome. Thanks so much for sharing.. How does this not kick back cycle errors? between the control driving the joints driving the surface, driving the position of the control ?

Answer: Jeff Brodsky

The control and the follicle are in a separate hierarchy from the joints. There’s no loop on the rotate value because the control is parented to the follicle so it’s just an offset from the follicles rotation… not the actual follicle rotation.

One thing I had to do which I forgot to mention in the video was add an extra grp above the ctrl to negate the ctrls rotation… without that the crtl gets double rotation… it’s double but no loop 🙂

8 replies on “Rigging Tips and Tricks : Variable FK rigging with Mentor Jeff Brodsky”

This course looks very interesting, it’s exactly what I need. Is this course discontinued? I didn’t see it in the drop down when I went to sign up.

Brilliant solution! Thanks Jeff for sharing. Do you have any tips for managing so many copies of such complicated node graph? Did you have to write a script to generate and make edits to the graph?


So elegant – I hate to think of the mess I’d have got into if I’d been asked to solve this!

Thanks for the share – very inspiring

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