Wandering registration

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BunyanFilms
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Wandering registration

Post by BunyanFilms » Thu Sep 13, 2007 12:56 am

Is it just me or am I missing something.

Every time I'm trying to animate characters walking around I get big drifts between key frames. The way I've been working is to get a major pose correct first, early in the sequence so I can build the action from it. However as soon as I get things moving I find the initial key frame's registration starts wandering about. I began trying to lock certain bones, like feet, but found that things would start popping around even worse. So in the end I have started using reference markers for things like when a character's foot hits the ground. This works out OK but I still find I need to make a lot of key frames just to stop the thing wandering off the registration.
Here is a scene where this was happening. Is it the way I setting up the characters?
http://www.bunyanfilms.com.au/hightower ... ation.anme
It seems I spend a lot of time redoing frame registration every time I add a later key frame. Do others get this problem?
myles
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Post by myles » Thu Sep 13, 2007 1:48 am

I think you may be seeing the different between pose-to-pose thinking and non-linear animation software.

I suspect you are using the Rotate Bone tool, which adds a keyframe only for that specific bone, instead of the Manipulate Bone tool which adds keyframes for all bones in that IK chain.

So, if you keyframed (using the Rotate Bone tool) both the thigh and shin bones on frame 10, the shin bone only on frame 20, and the thigh and shin on frame 30, you would see the thigh moving from frame 10 to 30 (apparently "drifting") rather than from frame 20 to 30 as you may have expected.

Workarounds:

1. Touch each bone you want to keyframe with the Rotate Bone tool - just selecting it should be enough to create a keyframe - so you would need to select the thigh bone on frame 20, even if it didn't move.

or

2. Use the Manipulate Bone tool rather than the Rotate Bone tool - some people feel this gives them less control, others feel it has a more puppet-like style of animating. Again, just selecting the shin bone should be enough to keyframe both it and the thigh bone.

or

3. If you are using the Pro version, try janimatic's key skeleton or key all scripts - see this thread and this location for the files. Keys the entire skeleton for that frame.

Regards, Myles.
"Quote me as saying I was mis-quoted."
-- Groucho Marx
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BunyanFilms
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Post by BunyanFilms » Thu Sep 13, 2007 2:06 am

Myles
I was using the manipulate bones tool or the bone resize tool when required. I think the main problems were occurring when I would set a key frame then try and position the character into a new key frame position. This would be set then I would find that the original key frame was getting adjusted by the second key frame. Can a different setting on the transition be helpful? I assume the effect of the wandering registration was not helped by the fact that then entire character layer was slowly reducing in size to get the characters looking like they were heading off in the distance.

I'll check out those scripts.
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slowtiger
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Post by slowtiger » Thu Sep 13, 2007 9:57 am

Walk cycles are an important part of my recent job. Finally I found a reasonably fast workflow for doing them, no matter from which side the character is seen. I'll sketch it here, in shorthand, assuming you're all familiar with AS.

1. Put your character into a group layer.

2. Create a line on the ground for reference.

3. Create the first walk pose, following the recipe from Richard Williams' "Animator's Survival Kit": front foot in contact with ground, back foot still in contact. Move only leg bones. Use the Transform Tool (Z), it's faster that way and you don't forget to key non-moving bones like you tend to with the Rotate Bone Tool (R).

4. Copy that pose's keys to some frames away. If you plan a walk with two steps per second, pose #1 will be on frame #1 and copied onto frame # 25. Set all keys to "linear".

5. Inverse that pose on frame # 13 (means, left and right foot exchange positions).

6. Choose the "Translate Bone" tool (T) and create keys for your character's root bone on # 1, 13, 25.

7. Go to # 7 and translate the root bone vertically until the foot which was front on #1 stands on the ground again.

8. Copy this key to # 19.

9. You will notice that the foot which was first on # 1 now slides backwards until # 13. Depending on the amount of accuracy you need you may need to adjust its vertical position in some or even all frames between 1 and 13. The same has to be done for the other foot between 13 and 25.

10. First foot needs to go to front from # 13 to 25. Create breakdown key first, at # 19. Take care at # 14 and 24 that the foot isn't under ground but clearly above. (This section of the walk is responsible for its character. By leaving the foot flat on ground for some more frames you get a tired walk, the way the leg is brought to front can be done in whatever fashion etc.) Repeat for other foot.

11. Now you have a character whose legs already walk "in place". If you want him to cross the screen, choose the group layer you placed him into. Choose the layer translate tool (1) and place the group layer where your character's walk should start. Set the end point as well. Set the keys to "linear". Your character will move across the screen, but his feet will still slide.

12. Switch on onionskin for # 1, 13 and 25. Move the end position of the group horizontally until the outlines of the feet match. Alternatively you can move that end position key in time.

13. Select all keys on #25 in all chacter timelines and set them to "Cycle, relative, 24 #".

Now your character should move across the screen with feet embedded in concrete. This workflow even works in perspective, just repeat point 11 for scaling the group layer. Tip: if you place its origin on the vanishing point of your perspective you get a much better result.

You could even start with not at first animating the character, but place the group layer positions first (a kind of "blocking"). If you have several characters moving at the same speed, it's easy to duplicate the animated group layer, replace the character in it, and start animating the walk. And this walk cycle doesn't have to have the same length as the first one!

I left out all other movements like arms and further body movements, but I think you got the principles.

(I wonder if anyone would be willing to spend some money for a "Moho cookbook" like this. I could write and illustrate whole chapters about those bread-and-butter animation basics ...)
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heyvern
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Post by heyvern » Thu Sep 13, 2007 11:13 am

Check out the Tips and Techniques section. I just posted a new rig (uses a layer script) that completely solves foot locking... with out using bone locking.

It does use a layer script and the skeleton rig is entirely based on the script.

-vern
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slowtiger
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Post by slowtiger » Thu Sep 13, 2007 11:57 am

This will just eliminate step 9, everything else still suffices. But I have to check it out - later.
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BunyanFilms
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Post by BunyanFilms » Thu Sep 13, 2007 1:40 pm

Thanks Slowtiger. I glad for once I seemed to be on the right track.
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