Sub-pixel grayscale three-dimensional printing

A method for processing a three-dimensional structure for printing by a three-dimensional printer at sub-pixel precision, comprising:

• (a) obtaining, by a data processing apparatus, a digital model of the three-dimensional structure, and slicing the digital model into a plurality of two-dimensional slices of the digital model of the three-dimensional structure;
• (b) mapping, by the data processing apparatus, a two-dimensional slice of the plurality of two-dimensional slices onto a two-dimensional grid of pixels, wherein the two-dimensional grid of pixels comprises a plurality of points;
• (c) calculating a number of the plurality of points within each pixel of the two-dimensional grid of pixels that overlap with the two-dimensional slice to determine a degree of containment of the two-dimensional slice with respect to the two-dimensional grid of pixels, and using at least the number to determine at least a first set of pixels, a second set of pixels, and a third set of pixels, wherein one or more pixels of the first set of pixels have a greater number of points than one or more pixels of the second set of pixels, and wherein the one or more pixels of the second set of pixels have a greater number of points than one or more pixels of the third set of pixels;
• (d) generating a light intensity level profile corresponding to the two-dimensional grid of pixels, which generating comprises assigning, by the data processing apparatus, (i) first intensity level of light comprising a wavelength or range of wavelengths to the one or more pixels of the first set of pixels, wherein the first intensity level is sufficient to cure photoactive resin during a predetermined curing time associated with the three-dimensional printer, (ii) a second intensity level of the light comprising the wavelength or range of wavelengths to the one or more pixels of the second set of pixels, wherein the second intensity level is less than the first intensity level, and (iii) a third intensity level of the light comprising the wavelength or range of wavelengths to the one or more pixels of the third set of pixels, wherein the third intensity level is less than the second intensity level, wherein the light intensity level profile corresponds to the degree of containment of the two-dimensional slice with respect to the two-dimensional grid of pixels;
• (e) storing the light intensity level profile corresponding to the two-dimensional grid of pixels in computer memory, wherein the light intensity level profile and the two-dimensional grid of pixels are usable by the three-dimensional printer to print at least a portion of the three-dimensional structure from the photoactive resin at the sub-pixel precision.