I have a love/hate relationship with "Lock Bone." Sometimes it works exactly like I want it to, and other times it seems to obey the whimsical laws of an alternate universe.
I wish I could rely on Lock Bone to keep a 'foot' perfectly nailed to a floor during the creation of a walk cycle--that would be awesome---but, unfortunately, sometimes a foot moves less when Lock Bone is left unchecked.
What do you think of Lock Bone? Do you use it to help you animate your walk cycles? Or have you given up on it?
Is there anyone out there so familiar with Lock Bone, that you use it often and have no complaints? If so, please tell me your secrets!
The arcane mysteries of Lock Bone
Moderators: Víctor Paredes, Belgarath, slowtiger
-
ink animations
- Posts: 24
- Joined: Wed Jun 27, 2007 12:33 am
- Location: UK
- Contact:
Maybe this will help you out?:
viewtopic.php?t=11457&highlight=bone+locking
To be honest I have only used it and got it to work how I wanted a few times - its like alchemy. I understand its a difficult problem though.
Cheers.
viewtopic.php?t=11457&highlight=bone+locking
To be honest I have only used it and got it to work how I wanted a few times - its like alchemy. I understand its a difficult problem though.
Cheers.
Last edited by ink animations on Fri Jun 19, 2009 1:18 am, edited 1 time in total.
Lock bones is based on an algorithm. A bone at the end of a chain is locked. An IK solver must calculate the rotation limits of all the bones above the locked bone. If the distances and lengths involved with those other bones prevent them from rotating freely you will get "pops" and "spins".
The success or failure of bone locking is determined by the chain of bones involved. If you don't set it up right it will fail. If you put the bones in awkward positions that the IK solver can't calculate realistically it will fail.
For example if you lock the feet of a character really far apart and move the hips, the leg bones might not have enough room or "play" for them to rotate before they "break" the IK solver. The locked bone is the "target" of the IK solver. If the distance to the locked bone stretches the limits of the angle for the bones in the chain then this causes pops and spins.
It isn't the bone locking that "doesn't work" it's where that bone is in relation to the other bones. You have to account for this. When locking bones make sure the other bones have room to rotate with out getting jammed up.
http://www.lowrestv.com/anime_studio/bo ... imbing.mov
-vern
The success or failure of bone locking is determined by the chain of bones involved. If you don't set it up right it will fail. If you put the bones in awkward positions that the IK solver can't calculate realistically it will fail.
For example if you lock the feet of a character really far apart and move the hips, the leg bones might not have enough room or "play" for them to rotate before they "break" the IK solver. The locked bone is the "target" of the IK solver. If the distance to the locked bone stretches the limits of the angle for the bones in the chain then this causes pops and spins.
It isn't the bone locking that "doesn't work" it's where that bone is in relation to the other bones. You have to account for this. When locking bones make sure the other bones have room to rotate with out getting jammed up.
http://www.lowrestv.com/anime_studio/bo ... imbing.mov
-vern
Thanks, HeyVern.
Let me see if I understand you. When I lock a foot bone and move some other bone, and the foot bone suddenly 'pops' out of location, what happened is that I created an impossible situation?--a situation where the foot bone cannot mathematically exist in that desired "locked" spot?
If that's the case, then why is it that I can occasionally unlock the foot bone and move everything as originally intended, and do it while keeping that foot bone carefully rooted in one spot?
Can the algorithm make mistakes? Because it seems to me that the algorithm sometimes thinks there's no way the foot can stay where I want it to stay, and then I unlock the foot and prove it wrong.
When that happens, I'm always like, "See? The foot could've stay there! I knew it!"
Let me see if I understand you. When I lock a foot bone and move some other bone, and the foot bone suddenly 'pops' out of location, what happened is that I created an impossible situation?--a situation where the foot bone cannot mathematically exist in that desired "locked" spot?
If that's the case, then why is it that I can occasionally unlock the foot bone and move everything as originally intended, and do it while keeping that foot bone carefully rooted in one spot?
Can the algorithm make mistakes? Because it seems to me that the algorithm sometimes thinks there's no way the foot can stay where I want it to stay, and then I unlock the foot and prove it wrong.
When that happens, I'm always like, "See? The foot could've stay there! I knew it!"
The difference between "doing it by hand" and "doing it automatically" is the biggest argument in animation. When you rely on automation you have to either take what you get or "tweak" the results. If bone locking based on mathematical calculations doesn't give you the results you desire than don't use it. Or if you do use it be aware of the limits.
If you drag a bone higher up the chain too far and the chain stretches to the limits of the IK solver then the locked bone will move. Don't move the other bones so far that the locked bone moves. Stop moving the bone when the locked bone shifts or moves. The purpose of bone locking is to allow for rotation of other bones in the chain more easily than doing it by hand.
In my sample animation it would have taken me ten times as long to key frame every frame of both the hands and the feet and all the leg and arm bones as the character "climbs". I would need a key on EVERY frame for the locked hands and feet. By using bone locking and staying within its limits I saved a bunch of time. I only had to unlock each foot or hand and move it up and the body while the other feet and hand stayed in place. If I went to far those locked bones shifted away... so... I didn't "go too far".
Automation is intended to help with, not replace, the work. The same can be said for inbetweening. Often the inbetweens created by ANY program are not good enough. You would have to tweak or do additional hand animation or add extra frames to "get it just right".
So yes, doing it by hand will give you more control. But it's a lot more work. You have to decide what you need. Once I figured out the limits and quirks of the bone lock and IK solver I haven't had much problem with it. It's just my own opinion of course.
-----
Someone here taught me a trick for locking feet and hand bones. Add an "extra" bone on the end of each. Lock THAT bone instead of the feet or hands. Now the feet and hands have some room to be rotated.
-vern
If you drag a bone higher up the chain too far and the chain stretches to the limits of the IK solver then the locked bone will move. Don't move the other bones so far that the locked bone moves. Stop moving the bone when the locked bone shifts or moves. The purpose of bone locking is to allow for rotation of other bones in the chain more easily than doing it by hand.
In my sample animation it would have taken me ten times as long to key frame every frame of both the hands and the feet and all the leg and arm bones as the character "climbs". I would need a key on EVERY frame for the locked hands and feet. By using bone locking and staying within its limits I saved a bunch of time. I only had to unlock each foot or hand and move it up and the body while the other feet and hand stayed in place. If I went to far those locked bones shifted away... so... I didn't "go too far".
Automation is intended to help with, not replace, the work. The same can be said for inbetweening. Often the inbetweens created by ANY program are not good enough. You would have to tweak or do additional hand animation or add extra frames to "get it just right".
So yes, doing it by hand will give you more control. But it's a lot more work. You have to decide what you need. Once I figured out the limits and quirks of the bone lock and IK solver I haven't had much problem with it. It's just my own opinion of course.
-----
Someone here taught me a trick for locking feet and hand bones. Add an "extra" bone on the end of each. Lock THAT bone instead of the feet or hands. Now the feet and hands have some room to be rotated.
-vern
Well, I guess that's the real problem: I am not good at predicting when the lock bone will work and when it won't.heyvern wrote:...Once I figured out the limits and quirks of the bone lock and IK solver I haven't had much problem with it. It's just my own opinion of course.
-vern
Nonetheless, I'll continue to use Lock Bone, because it's a great time-saver when it works. And who knows?...maybe one day I'll come to understand it's "limits and quirks" like you.
I'm going to try that. I'd really like to conquer Lock Bone.heyvern wrote:Someone here taught me a trick for locking feet and hand bones. Add an "extra" bone on the end of each. Lock THAT bone instead of the feet or hands. Now the feet and hands have some room to be rotated.
-vern
If anybody else has any tips on how to keep a locked bone from moving, or any work-around that mimics Lock Bone, I'd like to hear it.
-
Víctor Paredes
- Site Admin
- Posts: 5814
- Joined: Wed Jan 26, 2005 12:18 am
- Location: Barcelona/Chile
- Contact:
viewtopic.php?t=11457
Did you see this thread, right?
A tip to dominate lock bones could be remember the physical limitations of your character. of course, the imaginary physical limitations. Play with scale and translate bones too, there are more tools than rotate bones and they work like a charm when you want to make your character more alive. Adjust the keys where you are obtaining undesired results, correct an undesired pose, there is no way lock bones know exactly what you want, but if you help it to infer, it will help you back.
Personally, I use lock bones a lot, maybe more than anybody here, maybe I'm the guy who most use this feature in all world, who knows, but still unable to explain exactly how to use it well, so I think that are all tips I can give you. Oh, the last, experiment a lot, that should help
Did you see this thread, right?
A tip to dominate lock bones could be remember the physical limitations of your character. of course, the imaginary physical limitations. Play with scale and translate bones too, there are more tools than rotate bones and they work like a charm when you want to make your character more alive. Adjust the keys where you are obtaining undesired results, correct an undesired pose, there is no way lock bones know exactly what you want, but if you help it to infer, it will help you back.
Personally, I use lock bones a lot, maybe more than anybody here, maybe I'm the guy who most use this feature in all world, who knows, but still unable to explain exactly how to use it well, so I think that are all tips I can give you. Oh, the last, experiment a lot, that should help
Here's another lock bone tip:
If you notice a leg or arm that "flips" or bends the wrong way, just rotate that bone. True locking a lower bone in the chain does not let you actually directly rotate a bone higher up, but putting in a key and forcing the rotation of the "flipped" bone will often "pop" it back into the correct spot.
If that doesn't work then the locked bone and another bone higher up may be in a postion that prevents a "middle" bone from being exactly where you need it.
Imagine the hip bone is down low close to the locked foot bone. The two leg bones inbetween (thigh and calf) absolutely can not "fit" between the locked bone and the hip bone. It is physically impossible. They would be too long. There is no room to have them in some specific rotations. You would need to scale one of those bones, as selgin suggested, or adjust the position of the hip bone, raise it up slightly, so that the leg bones can readjust.
I think the main problem is that many people expect too much from the lock bone feature. And as selgin mentioned... it's hard or almost impossible to "explain" exactly how to make it work.
To be honest, I've encountered EXACTLY the problems mentioned. The difference is I understand WHY it isn't working as expected and I adjust it so it does.
-vern
If you notice a leg or arm that "flips" or bends the wrong way, just rotate that bone. True locking a lower bone in the chain does not let you actually directly rotate a bone higher up, but putting in a key and forcing the rotation of the "flipped" bone will often "pop" it back into the correct spot.
If that doesn't work then the locked bone and another bone higher up may be in a postion that prevents a "middle" bone from being exactly where you need it.
Imagine the hip bone is down low close to the locked foot bone. The two leg bones inbetween (thigh and calf) absolutely can not "fit" between the locked bone and the hip bone. It is physically impossible. They would be too long. There is no room to have them in some specific rotations. You would need to scale one of those bones, as selgin suggested, or adjust the position of the hip bone, raise it up slightly, so that the leg bones can readjust.
I think the main problem is that many people expect too much from the lock bone feature. And as selgin mentioned... it's hard or almost impossible to "explain" exactly how to make it work.
To be honest, I've encountered EXACTLY the problems mentioned. The difference is I understand WHY it isn't working as expected and I adjust it so it does.
-vern
Yes, that helped.selgin wrote:viewtopic.php?t=11457
Did you see this thread, right?...
Surprisingly, I'm now actually eager for the next locked foot-bone to pop out of location. Instead of grumbling and unlocking the bone as usual, I will shout, "That's what YOU think, bone!" and then I'll employ the various tips I learned in this thread.
I appreciate all of your tips, selgin. And HeyVern, I also appreciate your tips. I feel suffiently prepared for my next inevitable battle with Lock Bone.
I will be the Lock Bone MASTER!