the last cranky armature

Support Animation and Rigging
1

for the last armature problem, see the attached file, i need the lower armature to have the left part staying horizontal like the top one.
how do i do that, again i do not see any contstraints.
thanks all

Attachments

armatureHORIZ.blend (167 KB)

2

In that .blend file, the top armature is different than the first one you posted. Indeed, there are no constraints on it. It has an action that controls how it moves, open up an action editor to see. You will also notice that the bone that is by the wheel is not staying in position in relation to the wheel, that is it’s tip isn’t locked to PIN1. So if you had meshes attached to the bones and rendered it, it would appear broken, the “connecting rod” wouldn’t stay attached to the wheel, or “crankshaft”.

That file is a little misleading, the bottom armature appears to be only 2 bones, but actually there are 3 there, check the outliner. You can lock the rot of the one bone in the armature bones panel, but it doesn’t do anything because of the 3rd bone. The 3rd bone is part of the ik chain, because the constraint doesn’t have a chain len set to it, so all bones are affected by it. The bone roll angles are all screwed up as well, which isn’t helping things. In the 2nd armature ‘bone’ has it’s z-axis point in the world’s y-axis. Bone.001 has it’s z-axis point in the world’s z-axis, and bone.002 has it’s x&z-axis pointing in about 45 degree angle to the other bones.

I see you are trying to rig up a crankshaft, but for what purpose? What is going to control things? The wheel? I did a video tutorial showing one way to set it up, but my example will only work if it’s perfectly vertical, could be switched to be horizontal. But for any other angle a different technique would need to be used. MCollet has a text tutorial somewhere here on BA that will work in any orientation.

Link to my tutorial. And have a look at the attached .blend.

Randy

Attachments

armatureHORIZ.blend (168 KB)

3

Thanks Revolt_randy.
i watched your video - it looks different than 2.49b.
your file would not work in win7, it flashed a message about 250…
so it loaded but did not move.

my file it will be a train crank eventually.
thanks for showing the third bone. when i added the armature it was just a dot - now i know it was a bone just very small.
so with just 2 bones, which coonstraints should i use so the left bone just goes left and right?
thanks for your help

4

http://www.ctrc.org/gallery/v/Computer+Generated/Animations+_+Power+Point/
here is what i am building.
this post is about the big crank.
thanks

5

That example of mine will only work for a static model where the piston moves on the world’s x,y, or z-axis. For example, if your train’s piston moves perfectly horizontal and you are not animating the thing going up hill or turning, it will work fine. Otherwise you would be better off searching the forum for ‘crankshaft’ and a user name of ‘MCollet’ I think was his name. His rig will work in any orientation.

There was also a post in the wip section from someone by the name of Sir Gagrin (not the right spelling) about a small scale locomotive. I remember it because he needed to rig a worm screw/drive system and I gave him an example of using drivers in 2.5 for this. Anyhow, I know he had to complete linkage set up and working for driving several wheels, since steam locomotives had several drive wheels.

What’s the end of this project?? Just curious as I still own my childhood HO & N gauge trains, packed safely away in boxes.

Randy

6

The model will be static except all the wheels etc move.
camera will revolve round it.
i sent a PM to sir gagarin.
so as a staic model how will i do the piston thingy?
thanks

7

I was playing around with my example and actually it doesn’t need to be aligned directly with the world’s x,y, or z-axis if the limit location constraint’s CSpace is set to ‘pose space’. Of note, my method actually stretches the connecting rod bone a small amount, which cannot happen in the real world, but the only way you would notice is if you measured it with a ruler. I doubt your model will have a piston, since it probably won’t be visible, but you still need the piston bone there to anchor the connecting rod bone. Or use MCollett’s method, either one will work.

Randy

8

thanks
i was sent this link - maybe it will work in 2.49b
http://en.wikibooks.org/wiki/Blender_3D:_Noob_to_Pro/Advanced_Tutorials/Advanced_Animation/example/_Piston,_Rod_and_Crank#Piston.2C_Rod_and_Flywheel

it does not work in 2.49b
see attached
never found a parent to pixel thing.

Attachments

CRANKSIMPLE 4 .blend (168 KB)

9

model will have an open piston that can be seen
thanks

10

Revolt_randy, i wish i understood your tutorial - but i don’t

11

The method suggested there is at least twice as complicated as necessary, and even when you have assembled all the pieces it doesn’t really work properly, because there are circular dependencies.

Here is a sample of a working crank and piston rig:
[ATTACH]78890[/ATTACH].
If you need to do something significantly different, I suggest you post a .blend of the model you are trying to rig - I could’t figure out from the file you posted what you were actually trying to do.

Best wishes,
Matthew

12

Thanks Mcollet
that is EXACTLY what i am trying to do!
please explain - in simple terms - how it works.
i do have some difficulty understanding instruction
thanks again
eventually i would like to make the video near the bottom of this page
http://blenderartists.org/forum/showthread.php?t=190965&highlight=crank