Here is a breakdown of how to handle the workflow, specifically focusing on top-down alignment and general integration.
Drag your reference image into fSpy and align the red and green axes to parallel lines in the photo (like floor tiles or ceiling beams). fspy 3ds max top
Because of the variance between Y-Up and Z-Up software orientations, you may need to map the rotation values manually if you did not switch the preview axis in fSpy: fSpy X Rotation →right arrow 3ds Max X Rotation fSpy Y Rotation →right arrow 3ds Max Z Rotation fSpy Z Rotation →right arrow 3ds Max Y Rotation Here is a breakdown of how to handle
Because fSpy saves files in its native .fspy format (which is JSON-based), you need to record the mathematical parameters to manually input them into 3ds Max. This is by far the fastest and most reliable method
This is by far the fastest and most reliable method. The is a Python-based script designed to automate the entire process, pulling camera and image data directly from a .fspy file into 3ds Max.
Completely free with active script support for various 3D packages. Step 1: Calibrating the Camera in fSpy