How do I model buoyancy?

Hello all;

I am using the physics model and I want to know if anyone has tried to do floating objects. If I assume the water surface is a line and I have a physics object that over laps that line then some of it is out of the water. I want to calculate the area of the sprite that is below water level to get how much upward force to apply. Just an approximation would be good as a start. I can do it for a sphere, but an polygon is a little complicated--especially if I try to consider center of buoyancy vs center of mass. Has anyone tried to do something similar?

thanks for your time.

yours

winkr7

Here are two older ideas. I’m pretty sure they used a box as the collision shape but I think it could be updated to clip any collision shape by the water.

construct.net/en/forum/construct-3/how-do-i-8/floating-physics-140019

Thanks ROJOhound;

I will take a look.

ROJOhound;

I think your approximation to buoyancy works quite well. The four internal points is a very clever and it is short and simple and not hard to fit into my game.

Thanks again.

yours

winkr7

Glad it was useful.