Gravity Well:

_FxGraph3D (1/abs(u))*cos(v);(1/abs(u))*sin(v);-u;0.2;10;0;6.283;100;100;1;1;1;UV

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Alternate Gravity Well:
The 1 is replaced by c=2:

_FxGraph3D (c/abs(u))*cos(v);(c/abs(u))*sin(v);-u;0.2;10;0;6.283;100;100;1;1;2;UV

The UV may be replaced in the MoI window by SrfV, for a surface. etc

The math varies from simple, to calculus + relativity.
It would be fun to make a physical well. The well approximates the force on a ball, (Planet, moon, satelite, etc.) due to gravity of Sun/Earth, etc.
The rotation of the ball, and friction alter the physics. The well may be offset by the radius of the ball, so that the center of the ball is on the well surface...

https://www.spiralwishingwells.com/guide/Gravity_Wells_Mirenberg.pdf

https://www.youtube.com/watch?v=lV_uo1grl1Q

https://www.spsnational.org/sites/default/files/files/programs/2012/sock/2012-sps-sock-manual-final.pdf

A double well system model may be possible, if the math can be parameterized.
https://ia803404.us.archive.org/28/items/dli.ministry.28458/PRGN-1%25282%2529_160-164.pdf

- Brian

The use of _FxGraph3D is explained in the MoI Forum.
Copy the entire _FxGraph3d equation line.
In MoI4 or MoI5beta, press Tab, Ctrl+V, enter. etc


An x,y gravity curve can be made with _FxGraph with:
f(x) = -1/abs(x)
min(x) = 0.1
max(x) = 10.0
pts = 100
Then do a revolve around y axis.
The orientation is different than the _FxGraph3D version.