Empties/Cubes as IK Constraints/Solvers


(luckybreak) #1

Bear with me as I ain’t got the terminology down.
Q1.
The Character Animation Tools Documentation @ blender3D.com tell me:
“it is necessary to ensure that the local axes of each bone are consistent throughout the armature”
Does this mean pressing CTRL+A? this works on the armature as a whole, but not on the individual bones, am I doing it wrong? Or does the quote just mean build/extrude all your bones in the same view?
Q2.
Do Empties/Cubes make good IK constaints, solvers and nulls? Am I barking up the wrong tree as I can’t access them in pose mode?
I guess I want to use cubes as their orientation is easy to judge and I can create them in top view to align with world space. You know a kinda stable reference so I’m rotating/grabbing the bones through the cubes.

Cheers Big Ears lucky


(Hos) #2

Don’t worry about the quote, it is just there to throw you off. I’ve never had to worry
about it.

Don’t bother with cubes or empties – you can’t use them in the action window and this is
the strength of the animation system. As for orientations, it really doesn’t matter much as
once you have your IK constraint you can ‘grab’ the solver bones to pose the figure,
and thus there is no need for proper orientation.

Regards,
Chris


(Briggs) #3

Don’t worry about the quote, it is just there to throw you off. I’ve never had to worry
about it.

Well I don’t know about the context (never seen these docs) but I think this may have something to do with the roll handles and what view you draw the bones in and it DOES make a difference when you are mixing constraints (specifically rotation constraints). You can get VERY strange results if your not careful (I even had the wireframe representation of the bones themselves deform). Just had this happen the other day when I joined a hand armature to a body that I had created seperatly. If you never apply multiple/mixed constraints to any of your bones than you will probably never notice it.


(Hos) #4

Don’t listen to Zarf – he is just trying to throw you off! :wink:

Seriously though: yes those roll values can be troublesome (particularily
if you want to impliment the “paste flipped pose feature”), but I find
that unless you go out of your way to change them yourself, they don’t
get changed. Why would you want to change them? You wouldn’t, that’s
why! So, if you don’t ever play with the roll values you’ll be just fine.

Chris


(luckybreak) #5

Ok good advice - gave me the confidence to mess around.
On my limited attempts, its seems best to to not worry about axis or roll handles except for the “IK_Bones” these I make alignled with world space by editing the top and end points. Then when I move the hirarchy through grabbing the Ik_Bones I know which axis face where. It helped on my first walkcycle, providing that stable reference I was looking for.
But yep on the flipped side all the axis are opposite. At first I thought that wasn’t good so I adjusted the roll handles and subsiquently messed up pose flipping.