How to use Revit surface, find surface equation?

Revit
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How to use the Revit surface automatically find the surface equation?(Known XYZ points)
Similar to this equation

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1.jpg1188×636 136 KB

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See if these links can help:
http://dynamobim.org/math-transit/

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May I ask if it is possible. I am trying to figure this out too.
Thank you very much