Invert Existing 3D Relief

I already have a finished triangular STL model whose face carries a detailed textured relief. All I need now is the exact negative of that relief while leaving everything else exactly as-is.

Here’s the scope:

• Geometry preservation – the triangle’s outer shape, dimensions, and border stay untouched.
• Pure inversion – every raised feature must become recessed and vice-versa, with no rotation, mirroring, or lateral drift. Texture positions must match the original perfectly.
• High fidelity – the inverse surface should capture every nuance currently present; no loss of resolution is acceptable.
• Production ready – the resulting file must be watertight/manifold and pass mesh checks for 3D printing.

I work in Blender and would like the edit performed there so I can review the modifiers and history if needed. When complete, please send back a single corrected STL that fulfils the criteria above.

That’s the whole task—straightforward but detail-critical. Let me know if anything’s unclear, otherwise I’ll forward the source file and we can begin.