View Full Version : Asking for too much ?

04-11-2006, 08:24 AM
Simple LW request...make 1 object track another.

I thought this was to be so easy, but alas, I am lost.

In the enclosed scene I have 2 objects

object 1 is puller, object 2 is pulled.

Pivot point must remain at locations in each object

Object 2 MUST remain connected to object 1 at the point of the little tip in nose to center rear of object 1.

This creates an overall pivot point for both objects.

Object 1 follows path but I had to go in and key all rotations so it would match path as it has to turn before pivot of object 1 gets to turn.

(There must be a better way)

I could then go in and keyframe 2nd object for each frame to stay connected and moving with object 1 but

There must be a better way.

So the questions are

1. how would I keep the nose of obj 1 on the motion path automatically so I don't have to keyframe 1800 frames


2, How do I keep obj 2s nose connected to obj 1s tail without keyframing the next 1800 frames.

I don't think my compy would take the pounding after frame 759 :D

04-11-2006, 10:43 AM
One way to help this problem would be add a couple of bones to the base of the object and use the trailer plugin. I don't know if there is an easier way:)

04-11-2006, 11:19 AM
bones in non-organic objects? hmmmm

tried the follow plugin and as soon as I move anything the obj1 rotates 90 off, but follows null and obj2 just sits there twiddeling thumb knowing it can wait till frame 0 when everything comes back to it. :D

04-11-2006, 12:13 PM
bones in non-organic objects? hmmmm
Absolutely, it's a neat way of rigging a mechanical object if you don't want it in multiple layers. :)

04-11-2006, 12:32 PM
I altered only your scene. This solution (see motion options) doesn't like abrupt changes too much :)

04-11-2006, 03:38 PM
tried it and have to Ctrl-Alt-Del to stop it. runs like 1 frame per 10 min.
That can't be right.
It starts at frame 6 and the object with pointy nose is in front tho that's obj2 and should be pulled by obj 1

04-12-2006, 12:06 AM
Sorry, did it with a newer version.
Here's the modified scene for LW 8.5:

04-13-2006, 01:29 AM
it seems follower has some bugs.
try this (motion modifier):
The parameters:
Offset for curvature - how many meters in the future should be used for rotation alignment. if you use the objectlength head and tail are on the path
Max seconds to reach curvature - up to how many seconds in the future should be testet for paramter 1
Path from - movement of what object align to
Offset from pivot - how far should the pivot be from original position. For the leader it should be 0, the follower should use it's length
add to heading - your object is modeled in X+, so the same -90 as in the follower plugin should help.

04-13-2006, 02:15 AM

now I just have to tweak the timing so it *looks* like it's following :thumbsup:

HMMM strange, when I have the obj list on obj1 it runs realtime, on obj2 it runs about 1/8 th speed
but it works

04-13-2006, 03:03 AM
I tried it with the scene you posted. The layer1 object has about 10 position-keys over 200 frames (H and P rotation will be ovewritten at all). The layer2 object has no keyframes at all (it should take the motion from layer1 with a -5.6 offset). I also added a copy of layer2 with an offset -11.4. Here I can't see any breakdown. I restarted LW and reloaded the scene and still 30fps. May you post your scene, so I can see what happens?

04-13-2006, 09:15 AM

04-13-2006, 10:09 AM
I don't like to say this, but all your rotations (both objects) and all your position-keyframes of the layer2 object don't do anything. The script I wrote takes the x,y and z position of the curve at a specific time, iterate over the curve to find a point at a distance "offset for curvature" and overwrite the rotation and position accordingly (as also the Follower does).
It takes a longer time for Layout to move the layer2 to it's animated position and alter the position once more with the script, and this for every frame. So it's a little slower (but still in realtime here).

To have control over the motion, but use the basic motion of the script you will have to animate the object's x,y and z , bake the motion and remove (or disable) the script.

To take account of the object rotation within the script you would have to animate only the rotation-difference, and that's more useless than anything else.

04-13-2006, 10:55 AM
Went into Grapf Editor for obj2 and highlighted everything and deleted everything.

Runs just as fast now as obj1.
and follows good.

went in and just deleted ALL motions from everything
reset obj 1 motions (now only 2 keys) for the corners

and everything is hunky dory.

Cool :thumbsup:

Thanks for the time and your testing :thumbsup: :thumbsup: