Relightable free-viewpoint rendering allows a novel view of a scene to be rendered and relit based on multiple views of the scene from multiple camera viewpoints. Cast shadows in the scene are handled to allow local occlusion to be taken into account when determining irradiance estimates for the sample positions in the scene. This is achieved by determining an initial estimate of irradiance by ignoring local occlusion, then using that initial irradiance estimate with knowledge of the scene geometry to determine an angle-dependent radiance estimate for the scene. This radiance estimate can then be used with the knowledge of the scene geometry to determine local irradiance estimates at the sample positions within the scene.