The code must somehow compute bouyancy in a way that reflects the object's arbitrarily complex shape. It's likely carving the object up into some number of smaller primitive objects whose equations for bouyancy are known. In order to make the whole object move as one rigid body, though, it's probably computing force vectors for each primitive, and then summing them together based on the overall object's center of mass and moment of inertia.
My guess is that the object's mass and inertia is calculated in a way that is sensitive to the handedness of the drawing. The code probably takes the absolute value of the result so that right-handed and left-handed drawings both end up with positive mass. When you draw lobes though, the signedness alternates and cancels out, leading to less mass. With even numbers of lobes of near equal size, you end up with near zero mass.
The forces being computed on each primitive are probably representative of that primitive's true mass. Subsequently applying those same forces to a rigid body with significantly less mass therefore results in extreme acceleration. f=ma, f/m=a. f/0=explode.
My guess is that the object's mass and inertia is calculated in a way that is sensitive to the handedness of the drawing. The code probably takes the absolute value of the result so that right-handed and left-handed drawings both end up with positive mass. When you draw lobes though, the signedness alternates and cancels out, leading to less mass. With even numbers of lobes of near equal size, you end up with near zero mass.
The forces being computed on each primitive are probably representative of that primitive's true mass. Subsequently applying those same forces to a rigid body with significantly less mass therefore results in extreme acceleration. f=ma, f/m=a. f/0=explode.