Method and system for reuse of materials in additive manufacturing systems

A printing system for forming three-dimensional objects, layer by layer, the system comprising:

• a first inkjet printing head to dispense modeling material from a modeling material container;
• a second inkjet printing head to dispense support material from a support material container;
• a reusable waste material container;
• a third inkjet printing head communicating with the reusable waste material container to dispense reusable material conveyed from the reusable waste material container, wherein said reusable material comprises materials previously discharged from at least one of the first and second inkjet printing heads;
• and
• a leveling unit that removes surplus material from previously deposited layers of dispensed material, a bath wherein the surplus material is collected, a filter retaining solid particles through which liquid reusable waste material passes, and a tube conveying the reusable waste material to the reusable waste material container.