calc_heightmap_coords   Calculate voxel coordinates from a matrix where
                        values in the matrix indicate height above the
                        ground
calc_visibility         Calculate indices of visible voxels when
                        rendered from the specified view.
coord_align             Align the object with the given coordinates
coord_rotate            Rotate object around a coordinate axis
coord_translate         Translate object
gen_isosurface          Generate voxel coordinates defined by an
                        implicit function
gen_prism               Generate a rectangular prism centered at the
                        origin
gen_sphere              Generate voxel coordinates for a sphere
                        centered at the origin
isoaxesGrob             Create a grob representing the specified axis
                        orientation.
isocubesGrob            Create a grob of isocubes representing the
                        voxels at the given coordiantes
isolinesGrob            Create grob representing isometric grid of
                        lines
isopointsGrob           Create grob representing isometric grid of
                        points
obj_letter              Voxel coordinates for the letter R
obj_organic             Voxel coordinates for an organic shape
obj_test                Voxel coordinates for a test object useful for
                        debugging orientation and visibility checks
rand_palette            Generate a random colour palette
