Successfully animating a tubing connected at both ends

Hi ! Using “History”, I used to attach the end-circles as well as the first few centerline-curve points at each end of the tubing centerline curve, to the parent object at each end of the tube connecting them. I could THEN move one object one way, the other end object differently, and the tube connecting them would “keep up”. THIS time I was unable to include the centerline curve points at each end, with the end-circle, to the parent object(s) at each end. The end-circles attached successfully as a child object, but the centerline curve end-points wouldn’t select in the Parent/Child command. The “tube” would follow, but without the centerline curve, lost the integrity of its tubing-like shape. Have we changed how we do his ? Thanks for any possible help - C.

Could you please explain more. Maybe a graph (or a sample model)?!



Hi !

Which part did I lose you at ? Simple question first, then forward:

Any way to daughter curve control points to a parent object ?

If I want to move a part that has a tube connected to it, I’d like to use History to keep the tube connected, with it tweening properly between start-point and end-point of the parent-part motion.

I successfully daughtered the end-circle, but the centerline curve control points wouldn’t daughter, causing a motion-fail I used to be able to do.

Thanks -Animate Tubing & Connectors.3dm (2.9 MB)



Bongo isn’t really great in this kind of circumstances.

I guess you expect to animate the movement of the assembly part and hope the tube will automatically bend, shift and follow as they would in real life, right?.

Bongo lacks the means to do so.

What can be done is turn the procedure upside-down: animate the centreline of the tube (by means of morphing) and let the assembly part follow.

The trick to make an object ‘follow’ a curve is to Simple Constrain LookAlongZUp it to the curve by one single keyframe at tick 0.

I know it’s not easy to Morph a curve into a fluent move, certainly when it has a lots of control points. Whenever possible I try to reduce the number of control points to as few as possible. Another hint is to use only 2 keyframes (start and end) because the position of EVERY control point is fixed at each keyframe. Moreover there is no modification of tweening possible for Morphing; it’s 3D Cardinal spline and that’s it.

Animate Tubing & Connectors 001.3dm (1.4 MB)
In the model I used Pipe with History to create the tube. Updating the constraints in Preview isn’t flawless. And with History involved remember to continuously press the left/right arrows on the timeline-slider to get a Preview.

Hope this can work for you,


Luc -

Hi ! Thanks for trying.

No, I USED to be able to do this ALL the TIME. It was ABSOLUTELY SIMPLE. [ANSWER posted as a REPLY to this thread, below].

Simple point to this inquiry:
CAN defining points -like those defining a surface or a curve -

  1. Be animated and
  2. Be daughtered ?

We can animate AND daughter the Centerline-Curve and the end-circles, but now for some reason, the end-tangent direction mysteriously “flips” if you move the end-circle away from its originating location. Being able to daughter the first-3 end-points at each end of the Centerline-Curve would solve this. (Solution described below works WITHIN Limits: DO NOT include the Centerline Curve in your selections, DO use a circle Mid-way along the centerline curve to maintain Tube-end directions AND overall tubing shape - WITHIN limits … See below.)

I’ll keep experimenting, and IF successful, will post back here with results. _I’m CONFIDENT I’m overlooking something _ I USED to take for granted (rats !) . IF you ARE able to think of something either on your own, or with the input of others, discover a set of settings and procedural steps that get us there, could you share here ? I’m sure LOTS of us who do mechanical systems would like to know what we can do. We DON’T need a “Physics-ACCURATE” solution, just something that represents the action well enough to be convincing and reasonable.

I’ll keep experimenting, as - just as I mentioned at some point earlier - I’m CONFIDENT that I’m just overlooking something or getting a step out of sequence … .

Thanks again -


Luc -

Hi !

Ok, I think its a Sequence thing - within limits.

You can plainly see the centerline curve, and not as OBVIOUS, but in this pic you can make out the defining tube-end curve circles, too.

You can also see that the base ojects have “Moved” and that the Tube has followed as desired.

This ONLY works “within limits”, basically, don’t move the ends TOO far.

I’ll get a DETAILED sequence list to add here later, but for now -

Draw the centerline curve using “_curve” but with the PLINE curve as its skeleton. THEN use the _Circle command and select the _AroundCurve option, selecting the Centerline curve, and moving to the END of that centerline curve before picking. Enter the desired RADIUS. Do this again, put a circle at the OTHER end of the centerline curve (hit ENTER to repeat the Radius) . Put another mid-way.

TURN ON HISTORY. Make the End-circle a DAUGHTER of the end Object. Repeat this at the OTHER end. NOW use _Sweep1, select the Centerline curve, then in order, the 3 CIRCLES from one end to the other . Complete the sweep.

Each end-component has as a daughter, The end-curve “CIRCLE” at ITS end. Animate the movement of each end as desired. Use the circle MID-Way along the centerline curve as a visual adjustment for the result, IF NEEDED. IF the result of the movement doesn’t require it, you’re good. You can MOVE it, rotate its, elevate it, etc., as needed to maintain visual fidelity, thus mitigating SOME of the distortion this way, but again, only within limits. Minimize OVERALL movements, but within LIMITS you should get a workable result.

Its the MID-Way circle I was forgetting this time. THAT’s what keeps the running “shape” of the tube looking “reasonable”, and the End-Directions at each end of the tube under control. While it WOULD be better if we had access to curve points, THIS WILL Work - again, WITHIN LImits.

I remember mentioning to the person asking the LAST time this came up, that they would face the same “limitation”, but if they keep their movements “Reasonable”, the result would be useable !

Hope this helps ! I got SO focused on making the tube work with Control Points, I forgot the mid-way circle !

HAPPY to share -


ps.- command step sequence refinements forthcoming. I will likely replace the contents of THIS post (edit it) with the updated version. In the mean time, this WILL work - within LIMITS ;=) ! - C.

Short and (not) well,

  1. No
  2. No


Could you please post the model.
That would facilitate deciphering your writings.