Stress visualization within 3-dimensional particles could provide significant insights for understanding of the behaviors of complex particles. However traditional photoelastic methods are only able to produce simple particle shapes. Recently, 3D-printing has created new possibilities for enhancing the scope of stress analysis of physically representative particles. We report the results of X-ray computed tomography and 3D-printing, combined with traditional photoelastic analysis, to visualize strain for particles ranging from simple 2D discs to complex 3D-printed coffee beans, including internal voids. The relative orientation of the print layers and the loading force can affect the optical response of the discs without affecting the mechanical properties. Furthermore, a semi-quantitative measurement of the generated stresses within 3D-printed complex particle is presented. Potential limitations and areas of future interest for stress visualization of 3-dimensional particles are also outlined. • 3D printing photoelastic UV-curable resin enables stress analysis of complex particles. • Ray tracing confirms shadow at multiple faces of complex particles is from refraction. • Print orientation affects optical properties of 3D printed discs with applied load. • Semi-quantitative stress measurement can be obtained from complex 3D printed particles.