REQUEST: Feature ideas for forthcoming vehicle physics system...

[chandlerprall]

REQUEST: Feature ideas for forthcoming vehicle physics system...

[chandlerprall]

Physijs is built on top of Ammo.js (Bullet Physics), as long as that library supports these features I have no problem including them. From what I have seen of Bullet's vehicle system I don't think any of the above will be a problem - maybe the rear-wheel turning, but I think that can be worked around.

The articulation would have to come from a Point2Point constraint between two vehicle systems -- I'm working on finishing up the constraints now and should have them ready before too long.

[jayfield1979]

That's awesome news!

I can't wait to give it a go!

[chandlerprall]

Vehicle system now is in place and should support everything in your list - vehicle example

[jayfield1979]

That's fantastic! When I get some time I will check it out. Very much looking forward to experimenting!

Thanks for taking the time to let me know.

James

On 22 Oct 2012, at 08:25, Chandler [email protected] wrote:

Vehicle system now is in place and should support everything in your list - vehicle example

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[jayfield1979]

Hi,

Just been looking at the examples on your github home page and was wondering why they are now running so slowly:

http://chandlerprall.github.com/Physijs/examples/vehicle.html

There appears to be 2 FPS counters? Is this normal?

I still haven't had chance to play with or dissect the example code but thought I'd drawn your attention to it.

James

[chandlerprall]

The 2 FPS counters represent the graphics framerate (top) and the physics framerate (bottom). Which is running slow for you?

[jayfield1979]

Hi,

It's the bottom rate that rarely exceeds 12fps - is this normal? Is 12fps on the physics adequate I understand that it's obviously not bound to the fps. Do they run on separate threads? I'm on a top spec MacBook pro now.

James

Date: Sat, 27 Oct 2012 01:54:02 -0700
From: [email protected]
To: [email protected]
CC: [email protected]
Subject: Re: [Physijs] REQUEST: Feature ideas for forthcoming vehicle physics system... (#27)

The 2 FPS counters represent the graphics framerate (top) and the physics framerate (bottom). Which is running slow for you?

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[chandlerprall]

Few more questions: which example are you viewing and with what browser? Do you have a dedicated GPU or are you using integrated graphics?

The physics does run in a separate thread so it does not get in the way of rendering.

[jayfield1979]

My macBook Pro has NVIDIA GeForce GT 650M with 512MB of GDDR5 memory

On my iMac i7 which has a ATI Radeon HD 4850 512 MB, the bottom fps ranges from 12 - 25 fps

Both examples are of the car and boxes. It does look great!

Date: Tue, 30 Oct 2012 08:11:23 -0700
From: [email protected]
To: [email protected]
CC: [email protected]
Subject: Re: [Physijs] REQUEST: Feature ideas for forthcoming vehicle physics system... (#27)

Few more questions: which example are you viewing and with what browser? Do you have a dedicated GPU or are you using integrated graphics?

The physics does run in a separate thread so it does not get in the way of rendering.

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[chandlerprall]

What browser are you using?

[jayfield1979]

I have another question... how feasible would it be to only have your phisyics simulation apply to objects that fall in a radius of say a car or character? A bit like LOD but either physics applied or not...

That would certainly speed up simulation...

Date: Tue, 30 Oct 2012 10:23:33 -0700
From: [email protected]
To: [email protected]
CC: [email protected]
Subject: Re: [Physijs] REQUEST: Feature ideas for forthcoming vehicle physics system... (#27)

What browser are you using?

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[chandlerprall]

That is up to the broadphase to determine, and the ones in Ammo are very efficient as it is.

What browser are you using?

[jayfield1979]

I have finally got some time to play around with vehicle physics...

I have copied your code locally and replaced the models with my own...

My question is could you annotate the following properties so I know what I'm changing:

vehicle = new Physijs.Vehicle(mesh, new Physijs.VehicleTuning(
10.88,
1.83,
0.28,
500,
10.5,
6000
));

My meshes work (car & wheel) but their displacement is wrong (as the values I assume are based on your supplied Mustang model).

It is working very well but just looks odd :)

Very much looking forward to getting something cool out of this!

James

Date: Fri, 2 Nov 2012 13:25:25 -0700
From: [email protected]
To: [email protected]
CC: [email protected]
Subject: Re: [Physijs] REQUEST: Feature ideas for forthcoming vehicle physics system... (#27)

That is up to the broadphase to determine, and the ones in Ammo are very efficient as it is.

What browser are you using?

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[chandlerprall]

The parameters to VehicleTuning are, in order:

suspension_stiffness
suspension_compression
suspension_damping
max_suspension_travel_cm
friction_slip
max_suspension_force

[jayfield1979]

Thanks for that!

I have managed to get my models working with your example and changed a few settings to better fit the models:

http://frontier.lincoln.ac.uk/3d/development/Stage3/CarWPhysics/v2.html

There are some issues, which if you could help me with, I'd be grateful:

1. The car works ok but appears to hit invisible objects along the way. I assume this is something to do with maybe setting the diameter of the wheels but as the example I adapted uses your "addWheel" function, I can't see how I can change this.

2. My wheels face the same direction on both sides of the car.. wheels on the right need rotating 180 degrees - is this something I can specify without altering your script?

3. Is it easy enough to get my car to reverse?

Thanks in advance...

[jayfield1979]

p.s. I have resolved the issue 1 by removing the noise applied to the ground plane and changing it from a HeightField to a simple Plane.

My question remains however... do you have to manually enter a value for the diameter of the wheels or is it calculated?

[jayfield1979]

also... when creating a new vehicle can you pass other arguments to specify max power, steering offset, acceleration, etc...