I am trying to get an FTIR setup going and I need a good motion tracker for os 10.4.9. I cant get gridflow to compile, I love the pix_multiblob but its way to cpu hungry so I decided to write my own. I have never programed in C nor have I ever read any manuals but I'm willing to try. My question is do I need to know C before hand or can I get away with reading this: http://iem.at/pd/externals-HOWTO/ BTW I am not starting from scratch, if that were so I would never try this. I am trying to go the opencv route and wrap these for Pd: http://opencvlibrary.sourceforge.net/cvBlobsLib Anothe question is would it be easier to try to write it as a standalone external or as part of Gem like a pix_cvBlobs object? Where can I find information on developing for Gem like the externals how-to? Thanks, Alain