Usually, electronics 3D models flatten in physical prototypes because the digital design ignores real-world material properties (like thickness or rigidity) or uses incorrect manufacturing scaling.
Digital models often idealize parts—e.g., showing thin wires or flexible circuits as 2D lines—but physical materials need structural support to hold 3D shapes; a curved circuit without substrate thickness will flatten when printed or machined.
To fix this, check that your model includes accurate material dimensions (e.g., PCB layers, wire insulation) and test a small prototype section to adjust scaling or add lightweight supports before full production.