If you have ever tried to place a 3D render into a real photograph, you know the pain. You spend hours guessing the focal length, rotating the camera a fraction of a degree, and rendering test after test only to find your 3D chair is floating two inches above the real floor.

Because fSpy treats the Y-axis as "up," sometimes the imported camera is facing up towards the sky instead of down towards the floor.

: Use long, distinct lines in your photo for the red and green axes to increase accuracy. Avoid short lines that can lead to perspective drift. 🔄 Alternative: Built-in Perspective Match

: It can optionally import the unit system from your fSpy project to ensure correct scaling.