View Full Version : Vehicle submergance!

sean hargreaves
06-14-2007, 01:15 PM
I have a car that is travelling over a surface that has dips and rises in the road. They are'nt bumps, the road is just up and down over a certain distance. I'm having a heck of a time keeping the car from 'submerging' into the road. I need the tires of the car to linearly follow the dips and rises in the road. I know theres a way around this, my 3 manuals are'nt helping, and I'm new at this. Can anyone help please?

06-14-2007, 01:44 PM
i guess you could write an expression that would sample a point on an mesh along the Y axis using the xz world coordinates of the wheel and then decide the Y offset for the wheel factoring in its radius. Of course you would want to clamp the resulting output to limit the wheel travel to the suspension specs and maybe factor in stiffness using a sin/cos function.

or use this plugin


06-14-2007, 01:52 PM
if you have v9 - use STICKY - you set distance between both objects


06-14-2007, 02:01 PM
nice totally forgot about that one. but one thing thats kind of weak about sticky is its lack of effect blending. for example. if a car catches air off a bump, you would want to fade out the sticky to allow the tires to stay with the car once the suspension is exceeded. or have a sticky displacement limit distance that will turn off the influnce (and maybe allow for stiffness control)

sean hargreaves
06-14-2007, 02:09 PM
Guys, thanks for the tips, but remember, my car is'nt going over bumps, its following dips and rises in the road over a distance. Basically, my road is'nt flat, or bumpy. The car is'nt catching air, nor is the suspension being compressed. I just want the car to stay on the road and follow it. Any more suggestions? Please keep it simple.

06-14-2007, 02:27 PM
hi Sean, if it's not flat nor bumpy - what is it ? - please provide a pic for us to grasp what you mean.

also what version of LW are you working in.

I think you can key stick motion after the fact too.

sean hargreaves
06-14-2007, 02:45 PM
Its hilly.
I'm using LW 9.0

06-14-2007, 03:18 PM
Select points from the ground, create a spline and export it as a motion path.

sean hargreaves
06-14-2007, 03:52 PM
SplineGod, can you expand on that info. please?

sean hargreaves
06-14-2007, 04:26 PM
Did anyone read SplineGods info? He seemed to have turned off his computer milliseconds after he sent the message, damned boy!
Can anyone translate how I do what he said?

06-14-2007, 06:49 PM
In modeler, open your ground object. Select points from along your road and press ctl-p to make them into a spline. Copy this spline into a new object and save and send to layout.

Apply the Curve Constrain motion plugin to your car, and use the spline you just made. The car will follow the road. You can offsett the car if it's buried in the road.

sean hargreaves
06-14-2007, 08:21 PM
OK Dodgy, I follow you. But how do I copy the spline into a new object?

06-14-2007, 08:30 PM
The spline can be converted to a motion path or you can use it as a curve constraint. If you use the spline as a curve constraint just send it to modeler.

sean hargreaves
06-14-2007, 09:02 PM
Sorry SplineGod, but can you please tell me step by step? I've only been doing these for a short while.

06-14-2007, 10:35 PM
Curve Constraint:
Create spline, save it, load into layout. Look up curve constraint in manual, follow directions. :)

Motion Path:
Create spline, Use file-----export-----path to motion, save file. In layout select object and then load motion file onto object.

sean hargreaves
06-15-2007, 08:55 AM
Thanks SplineGod!