Oblate Ellipsoid

Major Radius:

Minor Radius:





Floor Area:

Surface Area*:



Radius @ Level:

Area @ Level:


Stemwall Surface Area:

Total Surface Area:

Prolate Ellipsoid

Semi Major Radius:

Semi Minor Radius:


Semi Base Major Radius:

Semi Base Minor Radius:

Base Perimeter:

Floor Area:

Surface Area*:

Half Prolate Surface Area:


Major Radius @ Level:

Minor Radius @ Level:

Perimeter @ Level:

Area @ Level:

Oblate Ellipsoid Dome Calcs Reference

Diameter of the base of the dome. The semi-major axis (a) of the ellipsoid will be defined as half of the diameter. (see diagram above)
Height of dome from base to apex. The semi-minor axis (b) of the ellipsoid will be defined as equal to the height. (see diagram above)
Vertical wall equal in diameter to the base of the dome extending from the base down to the ground. For half-ellipsoids -- where the height is equal to half the diameter -- the stemwall can usually be inflated as part of the Airform. These formulas are setup to only calculate half-ellipsoids. Orion style walls may be built if you choose, however, low profile spherical domes may be more appropriate. (see diagram above)
The ratio between the a and b of the ellisoid shape where 1.0 is a sphere, 1.35 is a moderately elliptical dome, and 1.45 is a highly elliptical dome.
Distance around the perimeter of the dome.
Floor Area
Area of the floor. The floor is defined as a circle equal to the diameter of the base of the dome.
Surface Area
Dome, Stemwall, and Total Surface Area describe the surface area of the dome and stemwall separately and then totals the two together.
Dome, Stemwall, and Total Volume describe the cubic volume contained by the dome and stemwall separately and then totals the two together.
The level above the base of the dome to calculate radius and area. (see diagram above)
Radius @ Level
The horizontal radius at the 'Level' specified. (see diagram above)
Area @ Level
Area of the circle described by the Radius @ Level.

Prolate Ellipse


A Prolate ellipsoid is a solid of revolution arrived at by revolving the ellipse around the long axis of the ellipse. The height of the half ellipse is the same as the b distance as it derived by revolution.

The ellipsoid will have more surface area to floor area than a spheroid.