I’ve been trying to replicate a project I did recently in Max. Basically, it’s one of those scooper type things that has a crane arm and is on treads. I got the model from this excellent Russian site http://archidom.net
Anyway, my problem is this.
As you can see in the picture above, when I rotate the arm (FH20arm2), everything moves fine(don’t worry about the piston, I haven’t set that up yet). However, when I rotate the scoop, I can’t seem to find a way to keep the top bone constrained to the arm.
What am I doing wrong? I’m pretty sure it’s a conceptual problem, as I ran into the same thing in Max, but found a way to do it and of course, Blender can do everything! :yes: So…
any idea’s ?
Hey, thanks for that. I’ve been reading the piston tutorial, but couldn’t work out how to constrain each bone for the scooper at seperate points. I haven’t started the actual piston part yet. I’ll have a look at the rod and crank tutorial, that might help. I feel it’s just a constraint away. .
But seriously, it turned out that I lacked parental guidance. I needed to parent the bones to an empty at the top of the ik chain. Then, I parented that empty to the swingarm (FH20arm2 in pic’s above).
Sleep rocks! And so does Blender!
I’ll probably see you all back here when I get stuck on another bit.
Until then, here’s a gif of it working. (Armature is hidden)
I’m stuck on the piston, now. I’ve got the piston to slide and track to the arm but, it doesn’t slide correctly and when I rotate the big arm, the piston follows but jiggles up and down a little bit. Also, when I clear rotation on the scoop, the top part of the piston won’t reset and sticks out at an angle. Can somebody have a look and see what I’m doing wrong, please.
If you look at the Selleri Piston tutorial, it says to have the center of those two pieces at the same place as their respective pivoting points, and then Control+t to track each piece to each other.
In other words, you take one mesh in the piston and in edit mode and move it until the mesh center is at the same location as it’s pivoting point. You do the same to the other mesh in the piston and then track each piece to one another. You might need to power track it as well, see the Selleri pdf for more details.
If this don’t work try the other tutorial. Gook luck!
Yes, I’ve read the Selleri tutorial. I’ve basically done what it says, using empties as the target for each piston half. Did you have a look at the file I uploaded? If I move the pivot point to the centres of the relevant meshes, it’s going to screw up the rotation of the piston. Anyway, the piston pieces seem to be tracking each other okay, the problem now is, when I rotate the arm that the piston’s attached to, the piston flops about and it flops about more, the faster it’s rotated. It sounds like it might be related to locked track constraint lagging one frame behind. I dunno.
I replied on the other thread you posted on but I don’t think you are having constraints lag a frame or anything like that (even the guy who had the original problem didn’t IMO) .
Like I said on the other thread :
you need to Ctrl A (apply scale/rotation) to all your parts after you remove the parenting relationship from Empty.001 and the armature and then reapply them .Right now they are all over the place
Go look at the Wiki tutorial and apply that technique . It is more “stable” then the Selleri method and locks up the various parts better .
