Because get_offsets() need to remain 2-D based for draw(), a separate function is needed to get and set the 3d coordinate data. Currently, one would set the 2d offsets, and then use set_3d_properties() to set the 3rd dimension data, which is awkward.

Perhaps this is an opportunity to create a function in the base artist class strictly for raw coordinate data? get/set_offsets() would then be intended more for display/transform purposes but would often be the same as the new methods. Also, this would help clear up confusion where some artists have get/set_array(), get/set_data() and get/set_offsets() all for coordinate data. A unified method would be valuable for documentation purposes.