IK Chain & Rigging

[Chris MacDonald]

Hey guys,

 

I'm in the process of creating an animation, and part of it involves trucks driving along roads.

 

I'm having some difficulty in animating the trailers so that they follow the tractor units (along a spline/path constraint). It seems to me that an IK chain would be the perfect solution to this, but I just can't quite get it to work.

 

Does anyone have any ideas as to how I'd achieve this?

[Chris MacDonald]

Right, sorted it I think.

 

You need to use a Spline IK rather than HI/HD solver.

[Josef Wienerroither]

You might also look at the freeware Toy Train plugin ( download for free at 3dsmaxplugins.de )

https://www.maxplugins.de/max2018.php?search=toytrain&all=on&sort=Author

Be sure to pick the correct download for your 3ds Max version

It's exactly designed for such tractor-trailer animation tasks

 

Big thanks to David Baker from 3dsMaxPlugins.de, who still does the recompiles for such hidden treasures !

[Chris MacDonald]

Ugh,

 

Any ideas why max would do this?

 

[Scott Dombrowski]

Sorry, I don't have a direct answer for you, but twisting with spline IK systems is a thing. This video may help get it sorted. This video I've done this with helper objects animated along path constraints. It's a hack job, but I needed to get the animation out the door.

 

I just looked at the file from the last time I did this almost two years ago showing a tractor and trailer going through a roundabout. I needed to show how the roundabout design accounted for how the trailer wheels don't follow the same path as the tractor's front wheels (offtracking). It's not pretty. I have two helper objects with path constraints. The tractor/trailer rig is linked to the first helper object which essentially pulls the rig along the path that the front wheels take. The second helper object is path constrained to a separate spline generated from AutoTURN (swept path analysis software) that is the path the rear wheels should follow. This second helper is slightly behind the rear axle of the trailer. The trailer object has a look-at controller to always point towards this second helper. It's not perfect and the trailer wheels do appear to slide a little when they go around the roundabout, but from a distance it isn't too noticeable and mostly achieves the offtracking effect required.

 

I do recall trying out the Toy Train plugin and it worked great for a train situation where everything follows the same path, but didn't handle the offtracking that I need.

 

Paul Neal used to sell a trailer rig but no longer does. I think he said the effort to maintain it outweighed any return he got from it. There's also Madcar, but I haven't gotten a chance to try it. It appears to be no longer developed, but they do recompile the plugin for new releases of Max.

 

Anybody else have any good solutions for trailers with offtracking?

Edited March 13, 2019 by nauticus27

[Chris Harris]

 

Anybody else have any good solutions for trailers with offtracking?

 

Not sure this qualifies as a "good" solution, but we use PTV Vissim for our traffic simulations and when you specify an HGV (semi) with a trailer, the file that's imported brings in blocks representing the semi(s) and the trailer(s).

 

We then are able, via Civil View (this is MAX 2016), to substitute in an actual semi model for each semi block, then I clone and align a trailer to the trailer block(s) and it works/offtracks. So essentially with this method, the only thing I'm doing is clone-align and that's it.

 

It's not perfect unless you have the exact trailer size and exact pivot point on the back of the semi...so the provided example is a little off but with some tweaking, i think I could get it spot on.

 

Here's a quick animation, notice how the semi is centered and the back of the trailer the wheels are on the line (a chopped down old file so excuse the mess):

 

 

The main problem with this is...you have to have PTV Vissim software and know how to use it. It's not a program you can really pick up without training or an understanding of traffic operations/planning, all our traffic engineers that use it have to go to training. I don't know how to use it other than take what is given to me and export out the files I need.

[Scott Dombrowski]

To avoid hijacking this thread any further, I've started a new one here: http://forums.cgarchitect.com/84925-vissim-civil-view.html

[Josef Wienerroither]

I had fun playing with this challenge, using the Toy Train plugin i mentioned previously

 

First i thought it to be a perfect solution, but of course i was wrong:

The Toy Train plugin always leads to the trailers folllow the exact same path as the engine ( but with a time delay ), while in real world, the trailers would follow the engine in the most direct path and direction caused by the pull force of the engine

 

The flaw of course is most obvious in tight corners ...

 

 

BTW: how can i embedd the youtube video properly ? ( i used the insert video button )

 

Nevertheless i share the scene here ( 3ds Max 2014 and the Toytrain plugin required )

 

Its still a start for the real solution. To make it the real thing one would have to control the trailer differently ( removing the toy train plugin ). Not sure if this really solveable with pure IK controller (without some experision or maxscript controllers ) , but i currently have no time to follow this idea further

Trailer_Offtracking_M2014.zip

Edited March 15, 2019 by spacefrog