A method of forming a three-dimensional object is carried out by: (a) providing a carrier and an optically transparent member having a build surface, the carrier and the build surface defining a build region therebetween; (b) filling the build region with a polymerizable liquid, the polymerizable liquid including a mixture of (i) a light polymerizable liquid first component, and (ii) a second solidifiable component that is different from the first component; (c) irradiating the build region with light through the optically transparent member to form a solid polymer scaffold from the first component and also advancing the carrier away from the build surface to form a three-dimensional intermediate having the same shape as, or a shape to be imparted to, the three-dimensional object, and containing the second solidifiable component carried in the scaffold in unsolidified and/or uncured form; and (d) concurrently with or subsequent to the irradiating step, solidifying and/or curing the second solidifiable component in the three-dimensional intermediate to form the three-dimensional object.