Complex sentence: Tradition and modernity meet in his works, with classical outline and geometric composition holding figures which border abstract art. Hartmann was seen as one of the up and coming artists of his generation and his works were well regarded by his peers.
Split into simpler sentences: Tradition and modernity meet in his works, wherein classical outline and geometric balance hold the characters together, but the figures themselves are pushing the boundaries of abstract. He was seen as one of the up and coming artists of his generation and his works were well regarded by his peers.