Method to reduce differential shrinkage in three-dimensional stereolithographic objects

A method of forming a three-dimensional object part in layerwise fashion by selectively solidifying a build material comprising:

• (a) solidifying a first fully cured layer of build material;
• (b) partially solidifying at least one partially cured intermediate layer of build material overlying at least a portion of the first fully cured layer by having liquid areas of build material and solidifying areas of build material, the solidifying areas not being adhered to the first fully cured layer after a curing done in a first scanning direction and being adhered to the first fully cured layer after a second curing done in a second scanning direction;
• and
• (c) solidifying a second fully cured layer of build material and the liquid areas of the build material in the at least one partially cured intermediate layer to thereby create a solid three-dimensional object with controlled shrinkage, the second fully cured layer overlying at least a portion of the at least one partially cured intermediate layer.