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Physics Simulation Scale
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fred64 Offline
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Post: #1
Physics Simulation Scale
Hi,
I was checking the PhysX sdk and I might have found a way to scale physX simulation so that i.e. 1 EE meter = 10 PhysX meters . This would allow to scale large areas i.e. for flight sims and such

We should have access to the following PhysX Header
PxTolerancesScale.h

PX_INLINE PxTolerancesScale::PxTolerancesScale():
length(1),
mass(1000),
speed(10)

As per documentation (below) for a flight sim where I would like to use 1 EE meter = 10 game meters I should probably use
length(0.1),
mass(1000),
speed(1)

gravity would be 0.98

Havent checked it yet but it should work based on my Physics knowledge...




Detailed Description
Class to define the scale at which simulation runs. Most simulation tolerances are calculated in terms of the values here.

Note:
if you change the simulation scale, you will probablly also wish to change the scene's default value of gravity, and stable simulation will probably require changes to the scene's bounceThreshold also.

Member Data Documentation
PxReal PxTolerancesScale::length

brief The approximate size of objects in the simulation.

For simulating roughly human-sized in metric units, 1 is a good choice. If simulation is done in centimetres, use 100 instead. This is used to estimate certain length-related tolerances.

Referenced by isValid().


PxReal PxTolerancesScale::mass

brief The approximate mass of a length * length * length block. If using metric scale for character sized objects and measuring mass in kilogrammes, 1000 is a good choice.

Referenced by isValid().


PxReal PxTolerancesScale::speed

brief The typical magnitude of velocities of objects in simulation. This is used to estimate whether a contact should be treated as bouncing or resting based on its impact velocity, and a kinetic energy threshold below which the simulation may put objects to sleep.

For normal physical environments, a good choice is the approximate speed of an object falling under gravity for one second.
(This post was last modified: 04-09-2013 03:33 PM by fred64.)
04-09-2013 03:22 PM
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