An in vitro method of preparing a bone tissue graft, the method comprising: (a) obtaining a digital model of a bone tissue portion to be produced, repaired, or replaced, wherein the digital model is partitioned into two or more model segments; (b) preparing two or more bone tissue graft segments, wherein each bone tissue graft segment has a size and shape corresponding to that of a model segment of step (a); and wherein preparing the two or more bone tissue graft segments comprises: (i) obtaining a scaffold, wherein the scaffold has a size and shape corresponding to a model segment; (ii) obtaining a culture vessel comprising a graft chamber, wherein the graft chamber has a size and shape corresponding to the model segment so as to accommodate the scaffold of step (i) and wherein the culture vessel is a direct perfusion bioreactor; (iii) applying one or more populations of cells to the scaffold; and (iv) culturing the cells on the scaffold within the graft chamber of the culture vessel for 3 to 5 weeks to form a bone tissue graft segment, wherein culture medium is perfused through the scaffold, and wherein the cells are induced pluripotent stem cell derived mesenchymal progenitor cells; and (c) assembling the two or more bone tissue graft segments prepared in step (b) to form a bone tissue graft, wherein the tissue graft has a size and shape corresponding to that of the bone tissue portion of step (a). (a) obtaining a digital model of a bone tissue portion to be produced, repaired, or replaced, wherein the digital model is partitioned into two or more model segments; (b) preparing two or more bone tissue graft segments, wherein each bone tissue graft segment has a size and shape corresponding to that of a model segment of step (a); and wherein preparing the two or more bone tissue graft segments comprises: (i) obtaining a scaffold, wherein the scaffold has a size and shape corresponding to a model segment; (ii) obtaining a culture vessel comprising a graft chamber, wherein the graft chamber has a size and shape corresponding to the model segment so as to accommodate the scaffold of step (i) and wherein the culture vessel is a direct perfusion bioreactor; (iii) applying one or more populations of cells to the scaffold; and (iv) culturing the cells on the scaffold within the graft chamber of the culture vessel for 3 to 5 weeks to form a bone tissue graft segment, wherein culture medium is perfused through the scaffold, and wherein the cells are induced pluripotent stem cell derived mesenchymal progenitor cells; and (i) obtaining a scaffold, wherein the scaffold has a size and shape corresponding to a model segment; (ii) obtaining a culture vessel comprising a graft chamber, wherein the graft chamber has a size and shape corresponding to the model segment so as to accommodate the scaffold of step (i) and wherein the culture vessel is a direct perfusion bioreactor; (iii) applying one or more populations of cells to the scaffold; and (iv) culturing the cells on the scaffold within the graft chamber of the culture vessel for 3 to 5 weeks to form a bone tissue graft segment, wherein culture medium is perfused through the scaffold, and wherein the cells are induced pluripotent stem cell derived mesenchymal progenitor cells; and (c) assembling the two or more bone tissue graft segments prepared in step (b) to form a bone tissue graft, wherein the tissue graft has a size and shape corresponding to that of the bone tissue portion of step (a). <EOS>