I don't use /3/ much at all, but I didn't see a dumb-questions thread, so I figure making my own thread for this is fair game.
See pic related. How come when I rotate the end joint it about it's local y axis it spins about a some other line? It even shows the right line I want to rotate about, but spins differently. I can do this just fine in max, but I need to explain 3D to people who can only install blender. Not saying one is superior. Here's the information I have;
The whole arm is IK rigged, as I was told you can only apply IKs to bones; there's a two-bone armature going along the first joint (shoulder) to the second (elbow) then from there to the end (wrist). The bones are a child of the grey base plate and have the finalmost piece as their target. The forearm and upper arm are each bound to their respective bones, individually. The large disk piece is bound to the grey plate and copies the Z rotation of the upper arm (world space - world space). The Final hand-part is free to be moved and is set to copy the Z rotation of the forearm (world space - world space).
Welp, I figured it out. I needed the end to be setting it's local rotation to the world rotation of the forearm. Thanks /3/. Stupid questions general if noone comes around to clean this off.
I tried to post hours ago but couldn't; you need to press R and then Y twice so it toggles from Global to Local (or Normal, if you have that set instead)
As to why it's happening, it's because you didn't apply Rotation (Ctrl A), which you often don't want to do
I should have said where the origins are: the end origin is at the center of the wrist, green axis facing out properly. The forearm center is at the elbow; upper arm and the disk both have centers at the shoulder, and the base has a center at the center of the bottom face.
So what I did is just put an empty plain axis at the wrist joint, move it out to the side along he y axis, then constrain the wrist to have its Y axis face towards the blank using the dampened track modifier. I'd like a better solution though, and his didn't work for the base for some reason. I'd like to be able to drag the base and have he arm fit accordingly.
Alright, sorry for all these duplicate posts; I'm saging myself.
I fiddled with it more and got the blank-axis idea to work, but it'd still be nice if I could just set one object's Y to copy the direction of another object's Y without affecting position. I mean with points and vectors I can do that sort of operation by hand, so I figure there's bound to be a means of doing it in blender.
This thread really annoys me.
What you're talking about is called Parenting. Ctrl P. You'll probably want to Parent them to an Empty (Shift A -> Empty -> whichever one you like, probably Axis)
Please learn the basics of Blender. Seriously, all of these concepts exist in other 3D packages, and like using other 3D packages, you need to spend a little time either with the documentation or with videos to learn how those softwares implement those features.
I'm trying to switch from Blender 2.4 to 2.7 but it's an unholy mutant spawn (2.4 is just an unholy spawn).
How do I change the number of vertices when I add a circle? I tried the decimate modifier but it doesn't offer much freedom.