Meshing Question What shape are the Hangars on Olympus

[dumbo2007]

So I am trying to approximate the shape of the hangars at Olympus base. They look like a squashed cylinder located at y = 0 and varying x or z.



These are the lines for the hangar in Olympus.cfg , line 43 to 46 :

HANGAR3
	POS 40 0 -120
	SCALE 40 10 60
END

So the scale is non uniform on the 3 axes. I am trying to create the collision mesh of this hangar in Bullet. Unfortunately the cylinder radius cannot be different. I have taken a cylinder around the Z axis and the z scaling was easy : length of cylinder = z scaling = 60 m

But I cannot have a Y and a X scaling of 40 and 10. I was thinking perhaps I can take a cylinder with a bigger radius and sink it into the ground a bit so that the chord length of the cylinder that touches the xz plane is 40 and the height is 10.....if you get what I mean. I am not sure about whether the curvature of the surface will match though.

I forgot high school maths the day I left high school so I am unable to come up with the distance to sink the cylinder

And yeah the co-ordinate systems are mirror images in the picture though that's irrelevant here

 

[orb]

From looking at it in the simulation with using different scale modifiers, the HANGAR3's roof seems to be a parabolic cylinder passing through (-ScaleX/2, 0, z), (0, ScaleY, z), (ScaleX/2, 0, z) in object local coordinates.

If that's the case, then a generic equation for parabola is (since the [math] tags don't want to work correctly, all will be like it was in C):

y = a * sqr (x) + b * x + c;

The parameters would be:

a = -ScaleY / sqr (0.5 * ScaleX);
b = 0;
c = ScaleY;

And the equation including ScaleX and ScaleY as parameters:

y = -ScaleY * sqr (x) / sqr (0.5 * ScaleX) + ScaleY;

The roof of course isn't exactly that curve but is segmented (it has 6 segments), but I haven't checked what points exactly it's using for vertices of them (except for the obvious, at y=0 and y=ScaleY), but I'm almost sure those points are defined by width and height of the door frame, which is somehow related to width and height of the hangar.

 

[dumbo2007]

OK, I ll need to think about how to use this info. Meanwhile I went with sunken cylinder - thats 60 meters long and 40 m in radius but located at y=-30. Gives a rough approximation.