Hi,
I’m currently experimenting with animated vehicle suspension. I’m using the PH_WHEEL with another PH_SLIDER constraint on top of that. This is due to the lack of ability to query the ph_wheel constraints “spring damper” slider offset. (I hope this explanation makes sense)
I also tried tracing from the undercarriage to ground, but its not very accurate.
So if anyone has any other ideas I would appreciate any input. I already suggested adding to PHCON_GETPOSITION the ability to query the “spring damper” offset, but it may not be so easy to implement.

I was trying to use bones in the suspension to match them to the wheel centers, but I can't seem to query this accuratly. Are you saying that the suspension poistion is not queriable? in other words it returns the position of the wheel, before any suspension changes?

Seems like we are both heading in the same direction

From manual:
Entities are allowed to rotate around axis 1 and axis 2. Use this constraint for setting up wheel-like behaviour instead of using two separate PH_HINGEs. For a car, axis 1 is the steering axis (left/right), while axis 2 is required for forward/backward movement. Only axis 1 can have angle limits and can have its orientation queried (phcon_getposition).

I think this means that you can only query the angle offset of the ph_wheel and not the "shock absorber" slider.

Dyc, your observations are correct. Unfortunately PH_WHEEL can not report its current position along axis 2. However, your trace approach should work. Or you could use getvertex for the center of the wheel and the center of the wheel mount and calculate the difference.

"Or you could use getvertex for the center of the wheel and the center of the wheel mount and calculate the difference"

Thanks Marco it's working nicely. But keeping in mind that you need to place the wheel mount vertex on the chasis and not on the animated part of the suspention.

I have done this with bones in the chasis suspension, have you done the same Dyc?

Works really well, thanks Marco

Yeah pretty much, I got the wheel centre vertex and the vertex that I used for wheel attachment and measured the distance the wheel travels in the y direction. Did some more calculations on the result to convert it to the 0-100 range and used that to animate the suspension.

Just for info: I have added 4 bones to each suspension strut, and assigned the vertex's from around the lower part of the suspension...



Then in script I get the position of the wheels center vertex and move the appropriate bones to match. Seems like a simpler way to do it, but both methods work. Just wanted to share with you how I am doing it

Nice !

Marco, I have uploaded a demo of the car in motion if it is of any use to you. Download Here