A three-dimensional digitizing method was used to assess the canopy structure of six Festuca arundinacea (FA)–Trifolium repens (TR) mixtures during the installation stage. Virtual canopy images were synthesized and used to derive light interception and partitioning between species. Computations from images were compared with a simple light model based on Beer’s law, in order to analyse within- and between-species foliage dispersion. The total leaf area index of the mixtures ranged from 0·6 to 4·5. The fraction of FA foliage overtopping TR was 9–30%. The mean inclination of FA and TR was 66 and 57°, respectively. Within-species dispersion parameters of FA and TR were about 0·8 and 1·0, namely clumped and random foliage dispersion, respectively. Although FA was sown in rows, between-species dispersion was random. Lower leaf inclination and lesser clumping in TR compensated foliage overtopping by FA, so that light partitioning between FA and TR (about 80 and 20%, respectively) was similar to the species contribution to total canopy foliage. Since between-species dispersion was random, a simple two-layer light model based on Beer’s law provided correct estimations of light partitioning (RMSE = 0·05), although light interception by FA was slightly overestimated because of its clumped dispersion.