A groundbreaking new approach [1] for the fabrication of complex photonic systems, especially such with off-axis optics, has been invented based on planar mounting in combination with a novel folding approach. Up to now volume production of photonic systems has been optimized for on-axis lens based optical systems. Chromatic aberration limits the usage or spectral range of these systems. Applying mirrors instead of lenses may help to suppress chromatic aberrations and wavelength depending absorption. The assembly of reflective optics, often in an off-axis configuration, is a complex process. So far most tools for volume production apply stacking of components in planar technology. Off-axis systems are typically assembled by more or less manually alignment of the components, which is not in favor for mass and low cost production of these systems. The novel approach utilizers a planar substrate featuring preprocessed bending lines. A high accuracy tool for planar assembly places the components onto the substrate. Then the sides of the substrate are bent leading to a predefined three dimensional body. The off-axis optical path inside is generated automatically. This concept is not limited to rectangular shapes but can also be applied to more complex systems, for example the so called "W-configuration" for a Czerny-Turner spectrometer. First tests of the "bend and place assembly" have been performed successfully on a camera setup to prove the working principle.