Process for forming integrated structures using three dimensional printing techniques

A process for making a three dimensional structure, comprising the steps of:

• depositing a powder material in a defined area;
• introducing a first binder material to at least one portion of said powder material thereby forming at least one region of a first type of solid material;
• introducing a second binder material to at least one portion of said powder material thereby forming at least one region of a second type of solid material, wherein said second binder material is different from said first binder material;
• leaving a third portion of said powder material unbounded by the binder materials, wherein said third portion has a generally smooth surface;
• removing at least a portion of said unbound powder material from said generally smooth surface of said third portion to form at least one void;
• and
• prior to completing the three dimensional structure and after the step of removing at least said portion of said unbound powder, repeating the steps of depositing said powder material in said defined area and introducing said first binder material.