Rigged character flip
Moderators: Víctor Paredes, Belgarath, slowtiger
Rigged character flip
I am looking for a solution to animate my character with targets on the feet doing a flip (example like a ninja jump and flip) and be able to continue animating after landing . I have tried several things but have been unsuccessful, it's not as easy as I thought. Thanks for any help or ideas, they are greatly appreciated.
Re: Rigged character flip
Yeah, I know what you mean, it can be very tricky.
My advice is to align the leg bones mostly straight, maybe only the slightest bend in the lower limb to help the IK. This way, you can flip the thigh bone horizontally (or, if the character design prevents you from making the knee joint 'straight', you can use a 'flipper' bone that has no strength or binding above the thigh bone.) This will flip the leg bone chain and the artwork.
I imagine the tricky bit you're running into is if you have Independent Angle enabled for the foot or ankle. The problem is that the bone won't flip to the opposing angle because, well, because it's not supposed to when you have this feature on. But of course, you probably want to keep this feature on to plant the feet firmly to the ground. What I do to work around this is I set a rotation keyframe for the foot or ankle before the flip key for the thigh, then correct the rotation after flipping the thigh. It's an extra step but not too bad once you get used to it.
Depending on how you've rigged the character's legs and feet, there can be any number other things to watch out for, but the above probably covers the most common issues for many basic rigging situations.
My advice is to align the leg bones mostly straight, maybe only the slightest bend in the lower limb to help the IK. This way, you can flip the thigh bone horizontally (or, if the character design prevents you from making the knee joint 'straight', you can use a 'flipper' bone that has no strength or binding above the thigh bone.) This will flip the leg bone chain and the artwork.
I imagine the tricky bit you're running into is if you have Independent Angle enabled for the foot or ankle. The problem is that the bone won't flip to the opposing angle because, well, because it's not supposed to when you have this feature on. But of course, you probably want to keep this feature on to plant the feet firmly to the ground. What I do to work around this is I set a rotation keyframe for the foot or ankle before the flip key for the thigh, then correct the rotation after flipping the thigh. It's an extra step but not too bad once you get used to it.
Depending on how you've rigged the character's legs and feet, there can be any number other things to watch out for, but the above probably covers the most common issues for many basic rigging situations.
Last edited by Greenlaw on Mon Apr 03, 2017 9:26 pm, edited 4 times in total.
D.R. Greenlaw
Artist/Partner - Little Green Dog | Little Green Dog Channel on Vimeo | Greenlaw's Demo Reel 2020 Edtion
Artist/Partner - Little Green Dog | Little Green Dog Channel on Vimeo | Greenlaw's Demo Reel 2020 Edtion
Re: Rigged character flip
Thanks for the reply! I will give your ideas a try. Thanks for the help.
Re: Rigged character flip
Sure, glad to help. BTW, it just occurred to me that even with the 'flipper' bone, chances are you're going to have to repose the leg after the flip, so you should keyframe all the leg bones in the frame before the flip.
An alternative approach is to make a 'flipped' version of the leg with its own rig. If you do a search, Victor demonstrated a very clever technique for swapping rigged body parts, and I recently used this technique in some rigs to allow the animator to swap between regular-jointed and noodle-jointed arms. I haven't tried this with legs but you should be able to use the technique to switch between a right pose setup and a left pose setup. For simple rigs, this might be too much to bother with, but it might be suitable for complex leg rig setups that don't 'flip' very well.
An alternative approach is to make a 'flipped' version of the leg with its own rig. If you do a search, Victor demonstrated a very clever technique for swapping rigged body parts, and I recently used this technique in some rigs to allow the animator to swap between regular-jointed and noodle-jointed arms. I haven't tried this with legs but you should be able to use the technique to switch between a right pose setup and a left pose setup. For simple rigs, this might be too much to bother with, but it might be suitable for complex leg rig setups that don't 'flip' very well.
Last edited by Greenlaw on Mon Apr 03, 2017 11:48 pm, edited 2 times in total.
D.R. Greenlaw
Artist/Partner - Little Green Dog | Little Green Dog Channel on Vimeo | Greenlaw's Demo Reel 2020 Edtion
Artist/Partner - Little Green Dog | Little Green Dog Channel on Vimeo | Greenlaw's Demo Reel 2020 Edtion
Re: Rigged character flip
I just saw that post by Victor yesterday. I definitely want to work on that concept. Courious if someone ever thought of a script that would allow one to easily achieve actions like cartwheels etc. Just thinking, thanks again.
Re: Rigged character flip
Technically speaking, that's what Regular Actions are for. Of course, you still have to first do the animation to create the Action. I don't think there are any shortcuts or substitutes for that. 
Once you have that 'Cartwheel' Action though, you can apply it as many times as you like and in any scene using that character. Or any character that has the same bone hierarchy. And, to a reasonable degree, if you use Convert to Relative, the other character doesn't even have to have the same body proportions.
Once you have that 'Cartwheel' Action though, you can apply it as many times as you like and in any scene using that character. Or any character that has the same bone hierarchy. And, to a reasonable degree, if you use Convert to Relative, the other character doesn't even have to have the same body proportions.
D.R. Greenlaw
Artist/Partner - Little Green Dog | Little Green Dog Channel on Vimeo | Greenlaw's Demo Reel 2020 Edtion
Artist/Partner - Little Green Dog | Little Green Dog Channel on Vimeo | Greenlaw's Demo Reel 2020 Edtion
Re: Rigged character flip
By the way, Love your work.