# Oblate Spheroid Class setting C

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Abhimanyu Choudhary on 12 Aug 2015
Answered: Brian Neiswander on 14 Aug 2015
Hello, I am trying to create an oblate spheroid object in matlab. I would like to specify certain parameters, more specifically, A,B,C of the ellipsoid. I can specify A,B directly using SemiminorAxis and SemimajorAxis, however, I am not sure how to set C.
Please tell me if there is any way I can specify this exactly.
Thank You

Brian Neiswander on 14 Aug 2015
Given the general equation of an ellipsoid:
(x/A)^2 + (y/B)^2 + (z/C)^2 = 1
The spheroid is a special case of an ellipsoid where "A" is equal to "B":
(x+y)^2/A^2 + (z/C)^2 = 1
This means that the spheroid is symmetric about its polar axis. When defining an "oblateSpheroid" object in MATLAB, the properties:
• "SemimajorAxis" defines "A" in the spheroid equation above
• There is no "B" to define because it is equivalent to "A" by definition
• "SemiminorAxis" defines "C" in the spheroid equation above
You can check the NASA SPICE Toolkit as it may provide some functionality for "triaxial" ellipsoids.
See below for more reference on ellipsoids and spheroids.