I'm wondering if anyone has come up with a good workaround for the weird crimping/creasing that happens when you use bones to animate an arm bending. Even in the "Anime Dude" project which is the default startup file for Anime Studio Pro, if you look closely at his left arm as it animates, you'll see this strange creasing.
If this were 3DSMax, I'd be working around this problem by adjusting the envelope strength at each end of the bone individually, modifying the bone shape, and adding custom angle-based deformations.
I've tried adding extra bones with angle control bone interactions, fiddling with bone positions and sizes, adding/removing details, etc. but nothing really yields acceptable results.
Workaround for elbow crimping with bone animation?
Moderators: Víctor Paredes, Belgarath, slowtiger
Thanks for the "fan bones" tip. Just for the sake of closure, my search yielded this thread, which looks like it has the answer:
http://www.lostmarble.com/forum/viewtop ... 70&start=0
http://www.lostmarble.com/forum/viewtop ... 70&start=0
Fan bones rule!
I've had more experience using bones in 3D, so the transition to AS was easy for me. I think I started using fan bones for joints almost immediately.
Luckily in 2D you don't need nearly as many to get the job done.
Another thing to keep an eye on... point placement around joints.
Even with a bunch of fan bones it won't work at all if the points aren't in the right place or you don't have "enough" of them. I found this to be a bit tricky especially with elbows. In some cases you want an elbow to bend both ways, but you like to have a sharp point on the inside of the joint when the arm is bent.
The key here is how to position the points so the overlap of the forearm and bicep looks correct. Make sure you use two separate shapes, split the arm into two shapes for the bicep and forearm. You want one or the other shape to overlap. Getting a perfect bend without overlap is tricky and often just looks really bad. The overlap can "hide" some funkyness in the bent joint. One shape can cover awkward areas of the other shape that don't need to be seen.
I have found I really only need two fan bones for an elbow. they stick out at 90 degrees on each side of the joint with apposing constraints at around 50% to either arm bone depending on which is the parent.
Then I will adjust those points so that they are moved correctly during animation. Use onion skin as you test this. Bend the bones in both directions on two separate frames and click on the onion skin for those frames while adjusting the bones on frame 0.
Another trick I discovered recently is "point offset". You move points "out of position" on frame 0 and put them back on frame 1. This allows you to change how bones effect a point. A point can be influenced by one bone but be in a totally different location from that bone during animation.
-vern
I've had more experience using bones in 3D, so the transition to AS was easy for me. I think I started using fan bones for joints almost immediately.
Luckily in 2D you don't need nearly as many to get the job done.
Another thing to keep an eye on... point placement around joints.
Even with a bunch of fan bones it won't work at all if the points aren't in the right place or you don't have "enough" of them. I found this to be a bit tricky especially with elbows. In some cases you want an elbow to bend both ways, but you like to have a sharp point on the inside of the joint when the arm is bent.
The key here is how to position the points so the overlap of the forearm and bicep looks correct. Make sure you use two separate shapes, split the arm into two shapes for the bicep and forearm. You want one or the other shape to overlap. Getting a perfect bend without overlap is tricky and often just looks really bad. The overlap can "hide" some funkyness in the bent joint. One shape can cover awkward areas of the other shape that don't need to be seen.
I have found I really only need two fan bones for an elbow. they stick out at 90 degrees on each side of the joint with apposing constraints at around 50% to either arm bone depending on which is the parent.
Then I will adjust those points so that they are moved correctly during animation. Use onion skin as you test this. Bend the bones in both directions on two separate frames and click on the onion skin for those frames while adjusting the bones on frame 0.
Another trick I discovered recently is "point offset". You move points "out of position" on frame 0 and put them back on frame 1. This allows you to change how bones effect a point. A point can be influenced by one bone but be in a totally different location from that bone during animation.
-vern
I don't know much about importing images and using bones on them but if your drawing is in AnimeStudio, I made a bone video tutorial. Requires Divx webplayer. http://www.lostmarble.com/forum/viewtopic.php?t=4942