# Weightlessness for individual objects, and a balloon with helium

Hello everyone

https://youtu.be/clERSmUr-CU

``````I was looking for how to give objects zero weight, and found a physically correct solution.

In the world there is no substance with zero weight, even helium and hydrogen have their weight. They are lighter than oxygen and nitrogen, and therefore rise upward - like oil in water.
``````

In BGE helium (hydrogen) will be the actuator Motion, with the Force +Z 9.8 мultiplied by the weight of the object.

Example: - if the mass of the object is 16, then for him the Force +Z will be 156.8 – weightlessness. 9.8*16=156,8. If you increase the force, the object flies up.

own.worldLinearVelocity*=.9
own.applyForce((0,0,(own.mass*9.8)),0)

Example blend: - balloon.blend (665 KB) note: sounds from the game/engine tesseract (http://tesseract.gg/), and do not scoff at the balloon.

Thank you for attention

Assuming even air distribution you could also use archimede force.
Give the object a volume variable in m³. If you know the average material density and mass, you can express this out of the both.
Now, assuming that the air is evenly distributed, you can give air a density rho, which usually is around 1.225 kg/m3.
Now you can use the formula F = rho * g * V to calculate the upwards force. The force will work in direction opposite to gravity.

So, for a balloon which’s weight is 0.1 kg and volume is 0.15 m³, in normal air density, temperature and humidity, the force would be 1.225 * 9.81 * 0.2 = 1.8025 (N). This would generate an upwards acceleration of 12.0175, which, summed with gravity, would end up being 2.20725 which would make the balloon accelerate upwards(pretty quickly in this example). Now you could apply the same formula for any other object with it’s mass and density set to something else and they would also perform very realistically

This is what you wrote - are you serious, man? Carefully, you’re in the frozen brain zone.

The theory is good, but I’m a bit confused with my brains :eek:… and where is so much realism needed then?
And you next time do not mold yourself cleverer :eyebrowlift:, but to make a working example and share it with people :yes:
Then for the scientist an easy warm-up, for me and many people already a difficulty …

And can you write a script for Brownian motion in a limited volume, or random appearance?
Like here: