more bodies = more force required?

I'm still just playing around with boxes. I have one box that is controllable with the WASD keys, like so:

if(m_InputReader->isKeyDown(KC_W))
myBody->addForce(Vector3(0,0,-50));


I set up code to dump a bunch of boxes in front of this box like so (this is where I create the moveable box and a bunch of ones falling in a line):

myBody = mScene->createBody("myCube", "Box01.mesh", new cubeShape(1.0f), 10.0f, Vector3(0,10,0) );

for(int i=0; i<10; i++)
mScene->createBody("cubes" + StringConverter::toString(i), "Box01.mesh", new cubeShape(1.0f), 10.0f, Vector3(0, 10 + i*10 ,-20) );




This looks pretty cool, except the first box no longer moves with the amount of force applied to it. I notice that the more boxes I dump into the scene, the more force I have to apply to the first box in order to get it moving. Why is this?

Yep.

The force is applied once every frame, less frame rate the lower the force is applied each second.

So say you want 500 newtons of force each second to a box. So you do "500 * timeSinceLastFrame".

Easy

Interesting. This behavior occurs with Vsync enabled. Are you talking about some kind of internal Physx framerate?

No, it's more independent on the Ogre frame rate. But since you have VSync enabled then, you can accurately predict the frame rate:

forceToApply * 0.01667

And to make the scene run at 60 frames per second, which is easier on the iterator:

mWorld = new world(...);
mScene = mWorld->createScene(...);
mScene->setTiming(scene::FIXED, 1.0f / 60.0f);


Now that should work

multiplying it by the timeSinceLastFrame seems to work pretty well, it seems to act the same way regardless of if I add 10 or 1000 boxes (1000 boxes is awesome, still getting 60 fps and it's all interacting perfectly. Awesome.)

I tried the setTiming call but got:
error C2039: 'setTiming' : is not a member of 'nxOgre::scene'

setTiming, I believe is new in 0.4RC3.

If you don't want to upgrade, you can use this code instead:

mScene->mScene->setTiming(1.0f / 60.0f, 8, NX_TIMESTEP_FIXED);