Yes I had troubles at first as well. I made 1 quant = 1 centimeter. What I did was calculate everything in SI units (ie. meters, kilograms etc). Then just before I applied my forces I converted them to my units (eg centimeters for length). For example: for a force in Newtons (ie kg.m/s^2) I multiplied the value by 100 to give a value in kg.cm/s^2. This gave the correct velocities of my entity in cm/s.

You have to be very careful with rounding errors when using "var" variable. To solve this I used "float" for all variables and only converted them to var's when required by the 3DGS engine.

To set the mass to the correct value I called the pX_setmass(myEnt,myMass) AFTER I called phent_settype(myEnt,PH_RIGID,PH_CONVEX). This set the correct value in PhysX.

Still hoping someone can help?