Optical property-based rendering of 3D prints

The increasing use of colored materials in 3D printing enables the creation of complex structures with realistic color appearances. Ensuring that the printed colors match the design requires advanced rendering methods to accurately predict the final product. We use a fully optical property-based pipeline for rendering the physically correct color of 3D-printed objects, achieving results nearly indistinguishable compared to the final printed samples. Our approach is based entirely on the intrinsic optical properties of the printing materials: the reduced scattering coefficient, absorption coefficient, refractive index, and scattering anisotropy factor. First, we employed an integrating sphere setup to measure the spectrally resolved absorption and reduced scattering coefficients of the base materials. This method was extended to handle both highly scattering and nearly non-scattering materials with precision. Next, a spectral Monte Carlo path tracing simulation was used to compute light transfer through the printed object, fully modeling the physics of light propagation in heterogeneous turbid media. Our results achieved CIE ΔE₂₀₀₀ values below 2.0, with renderings accurately reproducing the colors of the specially designed validation samples printed using a Stratasys PolyJet system. This pipeline provides a robust tool for predicting and optimizing the color appearance of 3D-printed objects. It offers broad applicability across various printing systems and material compositions while eliminating the need for time- and cost-intensive trial-and-error test prints.