Provided herein are methods of forming a three-dimensional object, which may be carried out by: (a) forming a three-dimensional intermediate by polymerization of a polymerizable liquid in an additive manufacturing process, the polymerizable liquid comprising a light polymerizable component; then (b) contacting at least a portion of the three-dimensional intermediate to a penetrant fluid, the penetrant fluid carrying a solidifiable component, the contacting step carried out under conditions in which the solidifiable component penetrates into the three-dimensional intermediate; (c) optionally but preferably separating the three-dimensional intermediate from the penetrant fluid; and then (d) solidifying and/or curing the solidifiable component in the three-dimensional intermediate to form the three-dimensional object.Provided herein are methods of forming a three-dimensional object, which may be carried out by: (a) forming a three-dimensional intermediate by polymerization of a polymerizable liquid in an additive manufacturing process, the polymerizable liquid comprising a light polymerizable component; then (b) contacting at least a portion of the three-dimensional intermediate to a penetrant fluid, the penetrant fluid carrying a solidifiable component, the contacting step carried out under conditions in which the solidifiable component penetrates into the three-dimensional intermediate; (c) optionally but preferably separating the three-dimensional intermediate from the penetrant fluid; and then (d) solidifying and/or curing the solidifiable component in the three-dimensional intermediate to form the three-dimensional object.