# Panda3D Physics: Units & Variables?

I’m getting some weird results in my particle physics, and I’m sure it’s all just my fault, but I wanted to check. Please tell me if I’m wrong about any of these!!

• Panda physics uses mks units for distance/mass/time (velocity is m/s, forces are all in Newtons, torques in N*m)

• Setting a force to be mass-independent makes it an acceleration

• The radius of a LinearDistanceForce is just a coefficient whose inverse square gets applied to the force

• Masses are measured in kilograms

imo

1. right
2. f=m*a, so if m=1, then f=a. so, in quantity, force = acceleration.
3. lineardistanceforce has a falloff type setting, linear/square/cube. radius means distance of the mass from the force source, an example case is, our moon is pulled by the earth .
4. right

Wait, LinearDistanceForce doesn’t detect the distance to the body it’s affecting??

I thought the dynamic was that I just plop it down at a position and it affects everything based on its actual position from every body it’s attached to and your falloff type, is that wrong?

The quantity in question is the float r in the constructor for a LinearSinkForce:
panda3d.org/reference/1.9.1/ … rSinkForce

oh, i read it again. radius should mean the max distance that the force source can affect. so your statement in 1st post should be correct.