I am a bit confused about character animation in blender. What I want to use is (as far as I understand), Inverse Kinematics. This means I move the foot the way I want it to move, and the rest of the legs bends accordingly (no?). I understand from the tuts I read that I need an IK solver for that, but I can’t find that option in the constraints buttons.
Right now, I have set up a walkcycle for a robot, but the feet do not move smoothly and slide a bit over the ground. I have a tut that deals exactly with this issue, but with the IK solver.
Also, what is the difference between IK and IKA? Which one of those is not available anymore (replaced by Armatures) ?
Don’t think I don’t want to search for myself, but I’m really stuck a t this point and never really know if what I read in the tut is still possible in the current blender version.
I don’t know which tutorial you are referring to, but this one worked pretty well for me: http://blenderchar.weirdhat.com/foottute/. It also adresses the sliding foot issue you mentioned.
You need to make an IK solver. There won’t be one automatically (yet).
As for IK/IKA: IKA’s were the name given to the old armature system. When someone talks about IKA’s, it’s sort of like they’re talking about the 0.5 version of armatures. IK refers to Inverse Kinematics, the calculation of the position of bones in a chain dictated by the location of the endpoints. It differs from the other method of bone placement, Forward Kinematics (FK), in which each bone in a chain inherets its position from up the chain.
How to make an IK solver:
Have a chain of bones.
In purple edit mode (TAB):
2. Select the endpoint (not the root) of the last bone in the chain.
3. Snap the cursor to this point (Ctrl-S)
4. Extrude a new bone from this point (e-key)
5. Create a new bone at the cursor point. Name it chain.acc.
The extruded bone you made in 4 is now a part of the IK chain of bones from 1. It will be your IK solver. The bone that created in 5 is not linked to the other bones. It will be your controller (thus the .acc suffix that I use to mean “actuator”).
In pose mode (blue edit mode, Ctrl-TAB):
6. Select the extruded bone.
7. Move the the constraint buttons (the chain links)
8. Click Add
9. Choose IK Solver from the popup menu that appears
10. In the OB field that appears, type the name of your armature (case sensitive, and at this probably just “Armature”)
11. In the BO field, type chain.acc
Select the chain.acc bone in pose mode, move it around and you should have working IK!
Although I can’t try it now, it seems as your explanation is the cure for my headache. But I wonder how somebody should know all that. Does not seem self-explanatory to me…
Ummm… I followed all the instructions, but moving the IK solver does not affect the armature. ‘IK solver’ and ‘const’ are written on a red background, which kinda tells me that something’s wrong.
Anywhere you can post or upload your .blend? Do it and give us a link. It’s probably something minor that you missed. We’ll have you up and running in no time.
You can take a look at the armature I have created and uploaded for you, to see if you are doing things any different. Moving the IK solvers certainly affect the armature in that file.
Aerosoy, thank you for the link. The IK works as I want, but I do not understand what is going on there. I could not reproduce it either.
Since your example is more complex than it is necessary to understand (yours is like the advanced example from blenderchar’s foot tute), I tried to make the easy version from blenderchar first with just three bones and the additional solver. I have no idea how to make it work, so i post the file here:
The bone called Solver was a child of the LowerLeg bone. I removed this. Also, you had a copylocation constraint on the Foot bone. I removed that. I removed the IK solver constraint on the Solver bone.
An IK solver constraint has been attached to the Foot bone, pointing to the Solver bone, which has been renamed Leg.acc, as it wasn’t really the solver for the chain, but the actuator (or effector, or whatever term you use).
