As being new to UE4, I’m testing simple scenarios and at this time I tried to learn how friction factor influence the object’s movement.
First experiment - zero friction
I set a physical material with zero friction for both, a floor and a cube, then add one shot of force of 1N to the cube within axis x:
- FPS = fix 40fps (so tick time step = 0.025s)
- Gravity = -2000cm/s^2 (just in order to have nice numbers)
- Cube mass = 1kg
- Physical Material Friction = 0.0
- addForce = 1N
The change of velocity should be:
- TickStepTime = 1/fps = 0.025s
- addForce = 1N
- velocity change after one shot of force = 1N*0.025s/1kg = 0.025m/s = 2.5cm/s
And this is exactly what I get
Second experiment - friction value = 0.025
At this time, the expected kinetic frictional force should be:
- weight of cube = 2000cm/s^2 * 1kg = 20N
- the kinetic frictional force should be then = 0.025 * 20N = 0.5N
The change of velocity after the force shot should be:
- TickStepTime = 1/fps = 0.025s
- addForce = 1N
- kinetic frictional force = 0.5N
- velocity change after one shot of force = (1N-0.5N)*0.025s/1kg = 0.0125m/s = 1.25cm/s
But the results are strange - velocity is not only at x axis, and there even ticks where the x velocity is negative as shown in the snapshot.
Even the first velocity value is 0.396 cm/s and is absolutely far from the expected value 1.25cm/s
I will be glad for a help for understanding how to fit the UE4 physics behavior to the expected values.
Thanks.
========================================================================
Settings and cube blp snapshots attached here
========================================================================
