Methods and compositions for forming three-dimensional objects by additive fabrication

1) A method of forming a three-dimensional object comprising the steps of:

• a. forming a layer of a particulate composition, the particulate composition comprising a plurality of first particles that comprise a resin component, the resin component comprising a first resin that is crystalline or semi-crystalline, the first resin comprising a first resin polymerizable group, wherein the layer of particulate composition has a dry temperature, the dry temperature being the temperature at the surface of the layer of the particulate composition;
• b. selectively depositing a liquid composition onto the layer of the particulate composition in accordance with computer data corresponding to the shape of at least a portion of a three-dimensional object, wherein at least one of the particulate composition or the liquid composition comprises an initiator capable of initiating the polymerization of at least the first resin, and wherein at least one melting temperature of the first resin is less when the particulate composition is in contact with the liquid composition than when the particulate composition is not in contact with the liquid composition;
• c. applying electromagnetic radiation to a plurality of the locations of the layer of the particulate composition where the liquid composition has been selectively deposited, wherein the particulate composition undergoes melting in a plurality of the locations where the liquid composition has been selectively deposited and while undergoing melting or while molten the initiator initiates polymerization of at least the first resin;
• and
• d. repeating steps a-c a plurality of times to form a three-dimensional object.