You are right about the potential leak and seen my limited skills in Python there is a good chance I leave a few openings. The only way can get actual data into MD is by having MD read a file from disk, and vice-versa i can ask MD to write data to disk. The API simply does not let me do more than that. For Poser in theory I could bypass the HDD and write the geometry directly from shared memory into the scene, but that would be unduly complicated and load a file from disk is/should be more easy to achieve. So: the information shared needs not be more than the reference to the file. This is prety small so if I leave a gate open the memory leak will be small.