Moho Animation Forum

BOY! Bones can be difficult to master!!!!

I built my stick figure man and got him all rigged and he worked fine, so I thought I'd play around with something a little more complex. But I'm stuck on the simplest possible problem.

I rigged the arms and legs the same exact way. The arms bend properly, that is, the arm vectors warp to fit the motions. But on the legs, the boots warp when I move the foot bone, but the knee does NOT warp when I move the lower leg bone.

I really wish there was a tool that showed EXACTLY what a bone was linked to.

Anyway, I've boned this guy, and re-boned him about 6 times and the result is always the same. The arms warp correctly, the boots warp correctly, the knees do NOT warp at all.

Here's the file. http://fiziwig.com/anim/bone_test.anme

Can anybody tell me what I've done wrong!?!

Thank you very much for any help. (This forum is AMAZING!)

--gary

Taking a wild guess... have you ever used Flash?

Doesn't matter really. Anyway the problem is the leg doesn't have enough points. Where the bones meet to make the knee there are no points. The thigh is a 4 point "box" so there is nothing to bend.

I mention Flash because it is also "vector" based except that it puts in many many many points, more than would be needed in most cases and the user doesn't have to know how or where the points are placed. A box shape in Flash might have 50 points, in AS you have to decide how many points to put in and the shape won't bend if it doesn't have enough.

When creating shapes for smooth blending you have to think about how the joints will bend. Where the points should be to maintain a consistent shape as it bends.

Generally I like to put in at a minimum, 3 points around a joint on "both sides". You have a center point which is the center of the joint. The two points on either side (in the case of the knee a point above and below the center joint point).

The bones that make up the leg (thigh and calf) would join in the middle over the center point of the joint.

I also moved the bones so they meet in the center and tweaked the bone strength so each bone overlaps the two center points of the joint. The other points around that joint are influenced by the closest bone. This keeps the shape of the leg as it bends.

Another thing I didn't do in the image below is "split" the leg into 2 filled shapes. basically connect the two center points with another line, make a shape for the thigh and a shape for the calf. When these shapes overlap as the leg bends it won't leave a "hole" in the fill. When a single fill overlaps itself it leaves a "hole", like a compound path in other drawing applications.



Hope this helps.

-vern

Thanks vern,

DOH!

So simple! Yet not really obvious at first. (I hear a voice in the distance: The evil programmer is laughing: Bwahaha. Silly boy. You have fallen into my clever newbie-trap!).

No, I never worked with Flash. The only "art" kind of thing I've done is still images with Poser 3 many years ago. I also did a lot of ham-fisted cartooning when I was a kid, back 50 or more years ago. (Oh, and a paint-by-number of a pheasant taking flight back around 1957.)

Thanks so much for the help.

--gary

fiziwig wrote:BOY! Bones can be difficult to master!!!!

--gary

But never fear the Bone doctor is always near.
Someday I may get the point of "Bones"

.
Bob P

A simple tutorial I made for bones.
http://www.renderape.com/animestudio/tu ... bones.html

J. Baker wrote:A simple tutorial I made for bones.
http://www.renderape.com/animestudio/tu ... bones.html

Thanks. Yes, In fact I used that very tutorial to learn how to do basic bones.

--gary