I recall reading in some recreational mathematics book (it may have been Godel, Escher, Bach) that one can prove the following: given any finite set of plane figures on planes at various angles, there exists a 3-dimensional object whose projections onto those planes are exactly those figures. As a corollary, this 3d object cannot be unique; to any finite set of plane projections, we can always add more plane projections, and construct an object to satisfy the original projections and the new ones. By choosing different new projections, one must have different objects satisfying the original set.
So strictly speaking, no, you cannot reconstruct a 3d figure from a finite collection of projections onto planes. However, with additional assumptions (such as continuity), you might be able to.