Benefetting from the recent improvement in resolution and wavelength coverage of infrared/submillimeter observations, we can construct panchromatic radiative transfer models of the stars and dust in galaxies. The construction of self-consistent, high-resolution 3D radiative transfer models of face-on spiral galaxies allows us to study the distribution, grain composition and emissivity of dust. We can furthermore investigate the main heating mechanisms on local and global scales within galaxies and infer how the heating by young stars can be probed most reliable.