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KillMe
05-04-2005, 08:19 PM
argh i'm infuriatingly close - descided to attempt to rig a character and set up a basic walk cycle - now i did this as a learning experiance and am generally ahppy with what i have achieved but there somethign hinky going on with the legs as i said its close but no cigar - could someone discect this and figure out whats wrong?

a3dmind
05-05-2005, 01:26 AM
I animate in messiah and I am not very familliar with Lightwave rigging but checking with your bones, I could see that when you turn off the ik limits the lower leg bone bends to the front! In messiah there is a +/- setting for that. If there is not such setting in Lightwave you may need to rotate the bank 180 degrees so that your bones rotate backwards.

a3dmind

nemac4
05-05-2005, 02:29 AM
here you go.

http://www.nemac4.com/files/walktest2.zip

Surrealist.
05-05-2005, 02:29 AM
OK, I am not doing much animation yet, but just from what I have read, you might think about investing in Timothy Albee's LW8 Character Animation. Basically the guy has it figured out from years of experience in rigging and animating. I have been reading his book and doing a little here and there but his approach is very simple and he has a lot of the pitfalls figured out. I've seen a few guys run into problems in rigging here on this site that would have been solved already had they had and used Tim's book. He really has some good systems worked out.

I think you can get it from wordware.

http://www.wordware.com/

No I don't get a percentage, just honest advice. Take it for what it's worth.

BTW: I downloaded the walkcycle. Good job and someboady already fixed it. Cool!

Think about the book, you have talent!

KillMe
05-05-2005, 05:49 AM
thanks for the help and advice guys

nemac4 you couldn't explain how you fixed it could you?

maybe i'll have a think about that book too

nemac4
05-05-2005, 07:11 AM
thanks for the help and advice guys

nemac4 you couldn't explain how you fixed it could you?

maybe i'll have a think about that book too

I set a key at -1 and reset the rotation of the shin bones and keyed them. I also set the thigh bones to keyframe interpolation.,.. but the main thing was the keyframes at -1 because lw needs to have a little prebend in the limbs to know which way it "wants" to bend with IK. .. or you can set up ik/targeting for the thigh to point at a knee target. :)

a3dmind
05-05-2005, 07:45 AM
So a +\- button in the bone options panel would be useful. Gotta love my messiah. ;)

a3dmind

KillMe
05-05-2005, 09:29 AM
if your used to lightwave is massiah difficult to learn? and does it intergrate well with lw?

spec24
05-05-2005, 10:07 AM
Killme - take Surrealists advice and pick up Tim's book. It's a heck of a lot cheaper than Messiah and you'll learn a lot.

Surrealist.
05-05-2005, 03:35 PM
-1 because lw needs to have a little prebend in the limbs to know which way it "wants"

As an exaple, the prebend tip is built into the way Albee sets up his characters ad is something he stresses from the begining.

Not to take anything away from nemac4 at all by any means so I hope that it is not taken that way, quite the opposite. The point is you can learn from others experince and cut down the curve and there are lots more just like what nemac4 did in this book.

Check out the image below. This is a character set for rigging from Albee's book.

Notice the prebends in the knees and the arms - this is before bones are added.

Just one of the many gems to be found there.

SplineGod
05-07-2005, 03:01 AM
Theres a lot of ways to set up bones. Its really easy to create a rig where you can repurpose the motions onto another character. The major joints are small bones pointed down the Z axis and the hold bones are separate bones. So basically you separate the rotation aspect of the bones from the holding aspect.
What you find out is that "prebending" the bones is a little misleading. What is actually happening is that you need the IK chain to form a triangle. If you have the pivot points of each bone in a straight line the IK Solver doesnt know which way the joint is supposed to bend and so it becomes unstable. For example if you have a hip, knee and ankle pivot points you need to pull the knee out of alignment with the other two. The direction you move the knee pivot will determine how it will bend.
If you have to use constraints to keep a joint from flipping or popping then you need to go back and fix the setup. Ive found that using constraints that way is usually just a bandaid and the rig ends up being unstable later.
What Ive found is that if you want stable IK in a leg you need to do three things:
1. "Prebend" the liimb
2. If you have 3D IK (IK on 2 or more rotational channels) on universal joints (like shoulders or hips) break that joint into 2 joints and apply 2D IK (IK applied to a single rotational channel) on each bone. For example have a small hip bone that gets IK in the bank so that the leg can move out to the side. Then the thigh bone gets IK in the pitch only. This will keep force the leg to behave in a predictable and stable fashion.
3. Animate the IK Goals in Arcs. I see too many people move IK Goals in straight lines and sometimes you can "stress" the IK solver when you get an IK Goal too close to the anchor or root of the IK chain. By moving the Goal in an arc you can avoid this. Things tend to move in arcs anyways. :)

Panikos
05-07-2005, 04:01 AM
I remember I had similar problems with LW5.6.
Prebend joints tells LW about the direction of the their rotation.
Also, aligning the bones (using small parent bones) gives proper orientation to the rotation ( I do this in messiah too)
I am sorry I cant help further on this.

Having prebend joints in the model makes it harder to texture the model too, something that I personally hate.

I've been using messiah since it was a LW plugin.
Messiah doesnt have such problems. I find it very easy to define IK-Chains and KneeConstraints resulting rock-solid IKs.