View Full Version : How to rig a truck ?

11-14-2010, 09:08 AM
Hi, I need to rig my model (see pic).
I know, vehicle rigger can do that, but I don`t have this plugin and don`t need complex rig. The vehicle is already animated, so I just need that trailer properly follow vehicle`s motion path.
Can you anybody help me please ?

11-14-2010, 03:53 PM
I would do it by hand :) best option then.

Anyway you can try Relativity and ask professor Dr. Delayer


vehicle Rigger costs 110 euros

11-14-2010, 11:54 PM
I need to animate almost 30 trailers at once so doing it by hand is little crazy. I think that I can`t use any delayer or follower because in turnings this trailers always goes on different paths than the vehicles.
My first idea was to use distance maintainer with target to connection point. But it works only in one axis.

11-15-2010, 12:48 AM
There is Vehicle Rigger:


I know it. But I don`t need full rig.

11-16-2010, 04:48 AM
I did a little test which i think achieves what you are after...

I created a spline to use as a motion path for the truck, then parented the trailer to that(with pivot point in the correct place).

Assign a curve constraint in motion options and set your desired frame time etc.

Then add a null object with the same curve constraint but delay the start and end frames so that it runs behind where you want the trailer to be.

I then added a couple of bones to the trailer to create an IK chain with the goal object being the delayed null.

I've attached a VERY rough scene for you to look at and I'm sure you'll do a better job of animating than I will ;)

Hope this helps

11-18-2010, 12:43 AM
Hi Simon, I am also playing with this setup few days ago, but I found it unusable because in turnings, this trailers always goes on different paths than the vehicles.
I need something more accurate.
Now I am trying setup with use of dynamic and it looks promising but it still need some finetuning. My life would be much easier if we have better dynamic in LW.

11-22-2010, 01:06 PM
I am only getting back into LW.

Isn't there an align to path command somewhere?
Could that be applied to the trailer?


11-22-2010, 01:19 PM
Have a look at this:

It might help....:)

11-23-2010, 12:53 AM
Ok, here is result when using dynamics. It isn't quite accurate, but perfectly shows difference between vehicle and trailer paths.
So, how to reproduce this without dynamic ?

11-23-2010, 02:42 AM
A second curve for the rear wheels of trailer?

Or an expression to position a null where you want the rear wheels.

Could you measure the angle of cab and trailer induced by the steering, and as you know the length of both, can you determine the length of the third side and the 2 angles. and hence the rear wheel position?

That might be a flawed idea, please let me know if it is. It's as much a question as it is a suggestion.

I am also not sure if you have a bone rig in the truck, or just rotating and pivoting objects.

Your question has me intrigued, I apologise if I am recycling bad ideas.


11-23-2010, 04:59 AM
Simon, That scene or object made my LW crash..

11-23-2010, 06:40 AM
What about Relativity: Dr. Motion Blender & perhaps Dr Follower

Define the path for the cab.

Define a second path for the rear, or a maximum offset for the rear wheels from the cab path, when the steering is at 100%. either I think could work.

Use heading from the steering to blend between the two paths.
It's a suggesttion to try, if you haven't.


11-23-2010, 09:44 AM
Hi Kevin, thans for ideas. No, I have no bone rig in the truck. Just rotating and pivoting objects. I am sure that this can be done with some math. I will try.

Best thing would be, if there will be possibility force LW to keep one object at a fixed distance to another one, working in all axes. But don`t know how.

11-23-2010, 09:55 AM
I did it the hard way.. Lots of info thanks


11-23-2010, 10:21 AM

Apologies if I am adding confusion, I've had 9.6 and 10 for 3 weeks now.
I hadn't touched LW since 5 and Inspire3d. I had kids :)

I just had ago at it, but I got stuck with my truck running backwards.
Ahuh .. a born again dummy.

I see it like this now, and you may be able to make it happen.

A null parented to the cab at the trailer connection point.
The cab aligned to the path.

As the front wheels steer, rotate the null at:

[variation] x wheel heading x -1

And have the trailer parented to that null.

I am not sure which is the best method to pass the expression around. But, I am pretty sure that simplistic math will work, but I'm struggling with the interface.

It's challenging me, I hope I am helping in some way.


11-23-2010, 01:17 PM
you don`t adding any confusion. I think that it is only my too bad english, so I am not able clearly explain what I want or understand your posts. Please be patient with me.
Your idea you posted looks very simply. I am going to try it. Thanks !

11-23-2010, 03:26 PM
Here's an oldie but may have some info that'll help.

11-24-2010, 05:10 AM
I must doing something wrong, nothing work. Can you anyone post a working sample scene ?