Complex sentence: Durable sculptural processes traditionally included carving (the removal of material) and modelling (the addition of material), in stone, metal, clay, wood and other materials and in the modern era were joined by assembly by welding, modelling, molding and casting.
Split into simpler sentences: Durable sculptural processes traditionally included carving (the removal of material) and modelling (the addition of material), in stone, metal, clay, wood and other materials. In the modern era were joined by assembly by welding, modelling, molding and casting.