Systems and methods configured to determine appearance of woven and knitted textiles at the ply-level are presented herein. Exemplary embodiments may: obtain an input pattern of a textile, the input pattern comprising a two-dimensional weave pattern; obtain appearance information, the appearance information including one or more of color, transparency, or roughness; determine ply curve geometry based on ply-level fiber details making up individual plys; generate an image simulating an appearance of the textile based on the two-dimensional weave pattern, the appearance information, and the ply curve geometry so that the image simulating the appearance of the textile takes into account the ply-level fiber details; and/or perform other operations.