3D porous and non-porous structures are designed and prepared by stereolithography using resins based on PTMC macromers. Tough, flexible network films prepared in this manner show E moduli of ≈3.8 MPa and high elongations at break >900%; tensile strengths are ≈4.2 MPa. These values increase with increasing PTMC macromer molecular weight. To reach suitable viscosities for processing, up to 45 wt% propylene carbonate is added as non-reactive diluent. The solid specimens have compression moduli of 3.1–4.2 MPa, similar to the values determined in tensile testing. The built porous structures show porosities of 53–66% and average pore sizes of 309–407 µm. The compression moduli of the porous structures are significantly lower than those of the solid structures.