ModelGeometry: sizes and orientations depend on sampling density and model orientation

[Maciej Komosinski]

Testing a ball (genotype //0\np:sh=1,ry=1\n) - balls have no specific orientation and are perfectly symmetrical so this might be an excuse for such dependence, yet... look at the example below. The first value in a line is the sampling density (0.1, 1, 2.5 or 4.3217452):

Windows+Visual Studio 2013 compilation, %g:

0.1 12.5664 0 [(2.0,2.0,2.0),Orient@(-0,1,0)]
1 12.5664 1.01829 [(2.0,2.0,2.0),Orient@(-0,1,0)]
2.5 12.5664 1.98001 [(2.0,1.9986484217435,1.97326669133902),Orient@(-0.415242,0.498119,0.472743
)]
4.32175 12.5664 2.97095 [(2.0,2.0,2.0),Orient@(-0,1,0)]

Windows+Visual Studio 2017 debug compilation, %.17g:

0.10000000000000001 12.566370614359172 0 [(2.0,2.0,2.0),Orient@(-0,1,0)]
1 12.566370614359172 1.2728649512171213 [(2.0,2.0,2.0),Orient@(-0,1,0)]
2.5 12.566370614359172 2.2275136646299623 [(2.0,1.9986484217435,1.97326669133902),Orient@(-0.415242,0.498119,0.472743)]
4.3217451999999996 12.566370614359172 3.1994853921717938 [(2.0,2.0,2.0),Orient@(-0,1,0)]

So for density=2.5, the computed orientation is weird.

Same test, this time linux+gcc, different result (%g for now):

0.1 12.5664 0 [(2.0,2.0,2.0),Orient@(-0,1,0)]
1 12.5664 1.01829 [(2.0,2.0,2.0),Orient@(-0,1,0)]
2.5 12.5664 1.98001 [(2.0,2.0,2.0),Orient@(-0,1,0)]
4.32175 12.5664 2.97095 [(2.0,2.0,2.0),Orient@(-0,1,0)]

Identify causes of this influence/non-determinism and eliminate if possible.