Dear Sir, Your answer has been helpful. Thank you. However.... I edited the file and did something like that movie record volume #8 transparency 0.95 wait 4 volume #8 transparency 0.9 wait 4 volume #8 transparency 0.85 wait 4 volume #8 transparency 0.8 wait 4 volume #8 transparency 0.75 wait 4 volume #8 transparency 0.7 wait 4 volume #8 transparency 0.65 wait 4 volume #8 transparency 0.6 wait 4 volume #8 transparency 0.55 wait 4 volume #8 transparency 0.5 wait 4 volume #8 transparency 0.45 wait 4 volume #8 transparency 0.4 wait 4 volume #8 transparency 0.35 wait 4 volume #8 transparency 0.3 wait 4 volume #8 transparency 0.25 wait 4 volume #8 transparency 0.2 wait 4 volume #8 transparency 0.15 wait 4 volume #8 transparency 0.1 wait 4 volume #8 transparency 0.05 wait 4 volume #8 transparency 0.0 wait 4 movie stop movie encode bitrate 1200 mformat avi output /Users/jean-paularmache/Desktop/pdbs_final2.avi with any lower or higher wait it did not function. Ok, having that I thought about doing the thing to two volumes at the same time, so I did volume #8, 9 transparency 0.95 wait 4 it did not function, therefore I changed the wait for a larger number. It did not work at all. The same problem as before. So, I did two blocks (copied the block for 8 and changed into 9) and applied the 4,5,6 etc waiting command. Nothing worked as before. However, I might have found one thing that might indicate to why it is like that. I noticed that while restoring the session, the histogram is not generated (and I work with BRIX files). To generate it and get the range, one just has to click on that file in the Volume viewer. If I don't restore the histograms, then nothing happens. If I restore the histogram for 8 and make it as a selected volume (that is selected in the Volume viewer), then the transparency steps work. However, if I restore the histogram for 8 and 9 and leave 9 as a selected volume, then nothing works. I am quite confused... :) Thank you for all the help Best regards, Jean-Paul Armache