#IK MAN…START RUNNING..
7 messages in this thread
Hi Jonas.
First of all Merry Christmas.
I have a little Q. :
I want to show the starting positions of several kinds of running (standing
then bending etc. <<like your IK woman flic I saw a month ago>> ).
I am using a Dummy object for the Torso, another one for L-Hand, another for
R-Hand, and two Dummys for both toes.
I moved the Torso down in frame 40 and both legs dummy horizontally left
(from the left viewport).
My problem is that both legs, from thigh to toe, shakes like an earthquake.
What can I do?
With Thanks
Sus.
PMJI,
Are the torso and leg hierarchies exclusive of one another? Put another way,
does the kinnematic chain of the leg include the torso or does the torso's
chain include either of the legs? What is the end-effector for the legs?
Do the legs move to the proper position as they are shaking?
– Phil
Hi Phillip,
<<Are the torso and leg hierarchies exclusive of one another? Put another way,
does the kinnematic chain of the leg include the torso or does the torso's
chain include either of the legs? What is the end-effector for the legs?
Do the legs move to the proper position as they are shaking?>>
The kinnematic chain includes the thigh,knee,foot and toe . The torso
is the parents but it is not a part of the kinnematic chain. the torso
I am moving use the dummy in the KF first and then calculating the legs
dummys and the hands dummys.
the legs move to the proper position.
Between my first letter and your answer I try to increase the
dumping to 0.5 and I don't know how, It kind of worked…. I don't
know what does it do, but It did it well….
Sus.
You may want to try positioning the torso by including it as part of a larger
kinnematic chain (perhaps by positioning the head). Performing an IK
operation on a single object, especially an ultimate parent such as the
torso, does not allow IK to distribute the solution – the torso is trying to
move and rotate. Because it's the legs parents, its slight rotations are
probably being passed down to the "quivering" legs.
Damping allows other objects in the chain to contribute a correspondingly
higher amount of rotation to the soultion. In so doing, it somewhat resembles
"stiffness". A damping of 0.0 allows the joint to move freely, 1.0 will
freeze the joint, and values in between stiffen the joint accordingly.
Hope your man is running now!
– Phil
Hi Phillip.
<<the torso is trying to
move and rotate. Because it's the legs parents, its slight rotations are
probably being passed down to the "quivering" legs.
>>
Yes, But I am not choosing the Torso in my Follow chain, only the
Thigh – to – toe. The torso I am moving in the KF and it doesn't shake.
Sus.
>> Yes, But I am not choosing the Torso in my Follow chain, only the Thigh –
to – toe. The torso I am moving in the KF and it doesn't shake. <<
But the torso is still the legs' parent, so its rotation(s) will be passed
along to its children (the legs). The solution may be to solve for your torso
first, and then the legs after. If the legs are still quivering, take a close
look at your joint paramters and their bounding boxes' orientations to make
sure they are correct.
– Phil
Hi Sus,
>> I want to show the starting positions of several kinds of running (standing
then bending etc. <<like your IK woman flic I saw a month ago>> ).
Are you refering to IKSPRINT.FLI? I can't add much to what others have
said. FWIW, I didn't solve all (any?) positions with IK. I simply pulled on
various body parts in Interactive mode to position them at keyframes. I found
this to be quite a lot of fun.
I believe I created a dummy object as a parent to the torso, which I
manipulated to keep the body as a whole where I wanted it relative to the
"ground." Also, I left one foot in place and dropped the other foot back,
rather than trying to do both at once.
I would like to go back and do it right sometime, actually solving the
motions with IK
.
Paul S.