Hydraulics/Piston Track To Constraint Help please.

Hello, I’m having a little trouble using the Track to constraint with my hydraulic.

As far as I know I have the settings correct, but when I move each piston they don’t track to the other. I tried changing the “Up” from Z to Y and X but when I do that I get all kinds of rotation problems (although it will track to the target that way.)

Below is the file in question so that you might better understand my problem.
If anyone could let me know how to fix this problem I would really appreciate it.


Dependency cycle detected:
largetube depends on smalltube through TrackTo.
smalltube depends on largetube through TrackTo.

I’m not sure did you want exactly that but hope this helps!


hydraulicsNew.blend (266 KB)

it does help but what if i wanted to attach it to a leg or something and have it compress when i animate the leg contracting?

Something like this?!:smiley:


Leg_hidraulics.blend (274 KB)

i love it now please explain

i’m still beginning wit riggin but i like the way this piston work

very nice little rigging

can you write a little PDf tut

if you cannot i’ll do the PDF but need some explaination to well understan it

hope you can give more details about it

Happy blendering

All my knowledge about Character Animation andRigging
is based on excellent tutorials:
All you need for Blender is here:
So…about Leg_hidraulics.blend …how to Rigging a Hand and a Foot is good tut too!
Only feel free to play with constrants to do what you want!
The problem was: two parts of hidraulics must to point each other.To avoid
Dependency cycle detected:
Bone.006 depends on Bone.005 through IK Constraint.
Bone.005 depends on Bone.006 through IK Constraint.

…using constrants I track Bone.005 to Bone and Bone.006 to Bone.005 so …that’s all.
Using IKSolver you can make all movement of hidraulics and manage it with Action Editor and NLA.
Thanks a lot for compliments!I will be happy to help for your future projects! :slight_smile:
All the best!

ok thansk for references

i will read this - but as i said i’m still anooby in terms of rigging
i did read most of the basic on rigging in wiki

but need lots of practice and example to have deep understanding about rigging

would you be able to make a small model of an engine piston
you know with piston head crank shaft rotatting which makes the arm and piston move up and down in a chamber

i mean i tried that before and could not find any good eample of it

appreciate your help a lot

i will definitively try to write a PDF for the piston and the engine rotating too

HAppy blendering

i’m trying to follow a tut here at

Noob to Pro/Advanced Tutorials/Advanced Animation/example/ Piston, Rod and Crank

have you tried this one before

i’m having problem to identify where to set the tip of the different bones

for the armature - the first armature

see dwg

can you help witht this one


I know it’s not perfect!!
Alt+A or Play …
Based on one Bezier Circle like path !joint is parented to path (Follow Path like every object with rotation obj1,obj2,obj3 ).Bone.001 with constrant Track To joint .
Тomorrow I will see about :


PistonRodCrank.blend (671 KB)

very nice

the only seems that you found another way to do it

can you explain a little how it works?

i can see that all the wheel are parented to a circular path

and there is only one bone

amazing to see it more simple than the original

but i still want to understan the first one the original one

here a few questions about this new model see pic

1 - is there a wiki page on the different symbols found on the outliner
theses seems to have changed?

2 - what is that sphere
seems to be part of ?
3 - what is that joint ?
seems to be part of the path on outliner

4 -the wheel seems to be made of several objects all parented to the path
why not have only one object can it works ?

5 - wou;d you be able to built a diagram for parent and constraints
as shown on the original tut
would be easier to undertand it and do a tut in PDF


How I have been told you it’s not perfect!
The problem was how to translate a rotating movement to a horizontal movement.
1.Exactly for that reason is BezierCircle like path and Sphere like joint(joint between Crank and Wheel).joint parented to path (Follow Path) and leave PathLenght:100 at the Curve and Surfase panel.So…rotation is OK.
2.What about horizontal movement(?) …yes …armature!The root Bone has to made that!
But connection ?Add Track To constraint to Bone.001 and set Target OB:joint.Now I’m sure that Bone.001 will follow horizontal movement of Bone and pointing rotating movement of joint.
3.All I need is to set the Bone movement :Pose Mode and Action Editor will make it easy!The trick of synchronization is to put tip of Bone.001 over joint.Go to frame 1 25 50 75 and 100 move Bone for each and set key-frame.
Everything else is “environment” and feel free to create what you like.:smiley:

Object … … …Parent

Wheel(every rotating object )…path(FollowPath)
Rod(like Cylinder in PistonRodCrank.blend)…Bone
like CurveCirclein PistonRodCrank.blend)…Bone.001
joint between Crank and Wheel)… …path(FollowPath)


Bone …LimitLocation(according to path R ) not necessity
Bone.001…TrackTo(Target OB:joint)

Yes you are absolutly right the wheel can be one object!
When I have to made it I point to idea not to rationality(like idea_PistonRodCrank.blend) and all rotating objacts in PistonRodCrank.blend are “quick build”.
-obj3 sphere is like wheel inside.
-obj2 add >BezierCurve + Bevel .2 > Alt+C to convert to Mesh>Array Modifier set count 8>Curve Modifier set Ob: path and Apply both Modifiers
-obj1 BezierCurve + BezierCurve inside +Extrude 0.1+Bevel 0.5 > Alt+C to convert to Mesh
-sphere is like connection between Crank and Rod
Note that select path > Shift + S Cursor Selection and after that have to create your wheel!
Yes ,I agree there are a lot of methods to do that!:stuck_out_tongue:
Please for your mercy and patience about me!
Sorry for my English!:o

Sorry …attachment!!!:smiley:


idea_PistonRodCrank.blend (245 KB)

i will study it this weekend and play with it to learn it

have you seen the one with a rotating circle
it’s another way to do it

i can upload file i you want

i’ m looking foqard to make
an ordinary motor with in line pistons

and also another one for a radial engine which seem to be more complciated

see pic

also you can see small animation a thi site

do you think it can be done with the technic you described


Happy blendering