A three dimensional optical setup system, comprising: a plurality of platforms (500a-500b, 600a-600c, 700a-700c, 800a-800b, 900, 1000a-1000b, 1100a-1100b, 1300a-1300b, 1400a-1400b, 1500a-1500b, 1600, 1700a-1700s, 1800, 1900, 2000, 2100, 3500, 3577-3578), each configured to releasably connect to one another to modularly construct 3D structures, wherein each of the plurality of platforms has a plurality of fixation locations (102a, 502, 602, 802) repeatedly arranged, wherein a constructed 3D structure defines a discrete 3D coordinate system of fixation locations located on a regular grid; and a plurality of modular optical units (1018a-1018f, 1118, 1219a, 1221, 1220d-1220g, 1220j, 1218i, 1218h, 1218m, 1218k, 1818, 2018, 1918,2118, 2218a-2218b, 2318a-2318c, 2444a-2444c, 2546m, 2548, 2550, 2552, 2654,2050, 2648, 2718a, 2718b), each having at least one mounting surface comprising complementary geometry to said fixation locations, wherein each of the plurality of modular optical units is configured to be releasably attachable to each of the plurality of platforms via the fixation locations, wherein each modular optical unit comprises an optical element (520, 1987), wherein, when the optical unit is attached to a fixation location, the optical element is centered with respect to the fixation location, wherein releasable attachment of some of the plurality of modular optical units at respective fixation locations defines a plurality of optical axes of first and second optical paths, wherein at least a portion of said optical axes overlap across said discrete 3D position coordinate system, and wherein, when the first optical path and the second optical path traverse an equal number of fixation locations, the first and second optical paths have the same length. a plurality of platforms (500a-500b, 600a-600c, 700a-700c, 800a-800b, 900, 1000a-1000b, 1100a-1100b, 1300a-1300b, 1400a-1400b, 1500a-1500b, 1600, 1700a-1700s, 1800, 1900, 2000, 2100, 3500, 3577-3578), each configured to releasably connect to one another to modularly construct 3D structures, wherein each of the plurality of platforms has a plurality of fixation locations (102a, 502, 602, 802) repeatedly arranged, wherein a constructed 3D structure defines a discrete 3D coordinate system of fixation locations located on a regular grid; and a plurality of modular optical units (1018a-1018f, 1118, 1219a, 1221, 1220d-1220g, 1220j, 1218i, 1218h, 1218m, 1218k, 1818, 2018, 1918,2118, 2218a-2218b, 2318a-2318c, 2444a-2444c, 2546m, 2548, 2550, 2552, 2654,2050, 2648, 2718a, 2718b), each having at least one mounting surface comprising complementary geometry to said fixation locations, wherein each of the plurality of modular optical units is configured to be releasably attachable to each of the plurality of platforms via the fixation locations, wherein each modular optical unit comprises an optical element (520, 1987), wherein, when the optical unit is attached to a fixation location, the optical element is centered with respect to the fixation location, wherein releasable attachment of some of the plurality of modular optical units at respective fixation locations defines a plurality of optical axes of first and second optical paths, wherein at least a portion of said optical axes overlap across said discrete 3D position coordinate system, and wherein, when the first optical path and the second optical path traverse an equal number of fixation locations, the first and second optical paths have the same length.