Wobbly wheels when using cannon.js instead of oimo,js

[basisbyte]

Hi guys,

First and most of all - thanks for creating this awesome piece of software. Really got me hooked and when I'm not working I mostly play around with babylonjs. Like a week ago I knew more or less null about 3D stuff and now I have cars happily driving around on my screen :). 

As you might have guessed, a question appeared.

Some months ago a guy around here wanted to make a monster truck for his son, and so there was a playground demo. Actually the car in there behaved like I wanted it because of the springs it gave a moving "chassis" and wheels feeling, depending on how hard its being accelerated or cornered, which is awesome. But its based on oimo.js and oimo  can't do heightmaps as far as I know - and purely flat streets are no fun :). 

So I tried to get the same car working with cannon.js but I simply can'get my wheels not to "wobble" like mad and even go sideways, as it seems like I can't find the setting to tell them to get more stiff as its done with the spring in the oimojs example (using the hinge2joint - which when I understood currectly from the tuts is the same as WheelJoint). Tried to find how its done in the raycast-vehicle-demo at cannonjs to find the nativeOptions to add them but now luck so far. 

A little bit of a wobble would be actually great as it adds to the realism. Playing around with the oimo example and different values I could get very close to a car behaving like I'd love it to behave - so old-american-muscle-car like.

Would be great if you could help me out - would be so happy if someday i have an old Malibu or the like cruising along a nice heightmap into the sunset  (Interstate 76 style - yay )

So here is the origonal babylonjs

http://www.babylonjs-playground.com/#1MSQGK#6

Here is the version with oimo.js where I got close to the behaviour I'm looking for (so much friction - so car flips to much, but not an issue)

http://www.babylonjs-playground.com/#1MSQGK#9

Here is the cannon js with wobbly wheels

http://www.babylonjs-playground.com/#1MSQGK#15

Here is an example where I tried to somehow add cannon.js native stuff (messes up a lot, because of trying and fooling around)

http://www.babylonjs-playground.com/#1MSQGK#18

Thanks a lot for your time guys, appreciate it

[adam]

I'm not seeing a Hinge2 joint for Cannon in the docs.

http://doc.babylonjs.com/overviews/Using_The_Physics_Engine

[adam]

Here is a car demo in Cannon:

https://github.com/schteppe/cannon.js/blob/master/demos/hinge.html

[basisbyte]

Thanks for the answer,

its far down on the page, like here

BABYLON.PhysicsJoint.Hinge2Joint = BABYLON.PhysicsJoint.WheelJoint;

and seems to work either - so the wheels are connected to the hinge and thats connected to the body - what I try to achieve is control of the wheels in terms of stabliity, which I think cannon.js is capable. So I try to find out how to make such a setting from cannon js working in babylon js - I think babylon can make use of such native settings where no streamlined command exists through

            nativeOptions: {
            } 

and   

          nativeParams {

          }

but I haven't found out yet how exactly

 

[RaananW]

So!

Cannon's down side is its hinges and constraints. Cannon has no hinge2 or wheel joint. you will have to "make" it by yourself (connecting 3 bodies with 2 hinge constraints, i guess), or use a single hinge. But then you don't get suspensions.

Here is a demo using Cannon's native RigidCar and Babylon together: http://www.babylonjs-playground.com/#UGMIH#8 

Here is a nice oimo.js demo - http://www.babylonjs-playground.com/#SFELK#3 with (kind of) suspensions and obstacles. 

Cannon's fallback to the hinge2 is the single hinge, hence the problems you had with the wobbly wheels.

[basisbyte]

Hi RaananW,

thanks a lot for your answer - okay, I understand. So I will try to get around the limitation in cannon.js or check if I can somehow avoid heightmaps in order to use oimo.js.

Is there any news regarding energy.js? - I couldn't find much information with googeling around. But speaking from the videos that are available, I think energy.js solves both issues, so I'd wait for energy.js if it isn't all too far away.

Have a nice remaining Sunday

 

[RaananW]

Energy solves a lot more

But sadly it is very time consuming. The beta version is already working (integrated into babylon's physics system), but there are still a few features missing. I hope to find time soon to fix everything.