An Introduction to CCD IK and how to use it

Hello all,
I recently did a talk about the CCD algorithm for IK and how to use the Animation Jobs system to implement it. Here are the slides for my Unite talk:
https://oc.unity3d.com/index.php/s/WDLkaj3S9rGYCH7
And here is the project:
https://oc.unity3d.com/index.php/s/IR6aKCQjQrrx4uW
Please note that this project was made using the 2018.2 beta and that Animation Jobs are part of an Experimental namespace. They are subject to change but I might not have time to update the project to match those changes, though I will do my best. Also note, this is not a complete solution for all things IK, just an introduction to the algorithm and how to use it. You will need to finish the implementation yourself in order that it is useful in a game.

 

@dev01 This solution for IK is only positional in that it doesn't have target rotations. This CCD algorithm is not ideal for what you are looking for. I don't know of an algorithm off the top of my head which would fill your needs perfectly but I'd imagine there are papers and tutorials out there which should help you write an algorithm which would work. I've had a few ideas for one I've been meaning to write myself but I haven't had the time! If I get around to it eventually, I'll do another talk like this one but I'm afraid that might be a bit too late for you.

Sorry I couldn't be more helpful.

 

@discofhc At the time of recording this was unrelated to Animation Rigging. However, I there is currently a branch of the Animation Rigging package with this algorithm in and I am hoping it will be merged with the master branch. If so you will be able to use this algorithm as part of the Animation Rigging package. However, the team's priority is to make sure what they have works and not to add additional rig constraints. As such it's unclear whether or not this will be added any time soon - it might, it might not. Sorry I can't be more specific.

 

@obucklin I don't have any experience on writing IK algorithms for physical robots so I cannot really speak with any authority on this. It is possible that a variation of the CCD algorithm would work when each bone is only rotated in the axis it can be rotated (rather than the free rotation I used in the talk). The problem with this is that it doesn't guarantee a solution and so you will need many more checks to verify that the algorithm isn't continuing indefinitely. It's possible that a FABRIK solver might be better for this situation - I'm not sure.

 

Ah... I may have messed up a bit here. Unity stopped using Owncloud and so that version is lost. I totally forgot that this project was being shared through Owncloud so I took no action to share it elsewhere. I still have the private repo somewhere but I did a lot of experimentation with the project after this talk so I'll need to find an appropriate place to roll it back to and then upload to another sharing location. I'm pretty busy at the moment but I will do my best to get another version ready this week.

Sorry about this, totally my fault.

 

Okay we're going to try Google Drive for sharing. Please let me know if this doesn't work.
Project: https://drive.google.com/file/d/17-zB_RjX_PJmdfx6hmq_QysXeIAIaxrZ/view?usp=sharing
Presentation: https://drive.google.com/file/d/11N2BAqyKV2Hoa9vSMw1--hwKXZsEKrTT/view?usp=sharing