Hi,

Sorry, I don't have a link on a tutorial to create an heightmap from a model.
It's only a possible workflow I found for your need.
I think it's possible with Blender to have a depthmap, but I haven't learned Blender yet.

So...

1/ you can export your model as STL file. Perhaps OBJ is OK too.
I don't have you file and took for the example a very old model of saloon, I made 30 years ago .


2/ import this mesh in the Meshlab program. You can find it here : https://www.meshlab.net/


3/ you go in the Tools/options menu to parameter the background top and bottom with white.


4/ in View menu, verify the options to avoid trackball and info Panel


5/ In the Render/Shaders, use the DepthMap shader.
Tune the sliders to have a grayscale.



6/ take a screenshot of the zone you want


7/ use your favorite bitmap editor to invert the colors.
The Moi's plugin to use heightmap use black to white grayscale.


8/ In MoI, use the heightmap plugin to have a serie of profiles


9/ use the Loft tool (using all the profiles) to create a relief.



It's not very orthodox use of MoI.
Apologies to Michael, the spirit of MoI is here deflected...