3d printing using phase changing materials as support

A cartridge for three-dimensionally printing, the cartridge comprising:

• a housing configured for insertion in a three-dimensional printing device;
• a recess in the housing;
• a first material within the recess, the first material comprising a Herschel-Bulkley material having a yield stress less than 100 Pascals;
• and
• an opening in the housing configured for an injector to pass through the housing into the recess and displace the first material with a second material,
• wherein the first material is permeable by focused energy applied to a region of the first material using a focused energy source.

An apparatus for creating a three-dimensional structure, the apparatus comprising:

• a container to hold a first material;
• a focused energy source configured to cause a phase change in a region of the first material by applying focused energy to the region;
• and
• an injector configured to displace first material in the region with a second material,
• wherein the first material is a Herschel-Bulkley material having a yield stress less than 100 Pascals.