Sometimes when working in a scene, I’d like to test several alternatives (different lighting sets, or rendering options) and compare the results, but this usually takes a lot of time.
I’m planning to prepare several versions of the scene and make a batch command (to be executed automatically during the night) that could open sequentially each of them, render it and save to a corresponding name, so next day I’ll have all the renderings.
If possible, I’d like to have also the time taken for each image.
Can anyone help with some ideas?
(Please excuse my English)
if you render in batch mode you will have printed timestamps of the rendering time in the console and you can make different setups in the same scene and keyframe each setup in a frame this way you will easily switch between them and will have a easy way to do what you want, i hope it helps.
Run blender from a comand prompt with -h to see the options.
I just did a test in windows XP, and the “-f” (frame) parameter appears to be mandatory. The -o (output file) seems to be optional, defaults to whatever path was setup in the file.
\blender243rc2.exe -b MyFile.blend -o d:/tmp/myFile.jpg -f 1 >>log
\blender243rc2.exe -b MyFile.blend -o d:/tmp/myFile.jpg -f 33 >>log
You can append to a log file with the “>>” operator, and it will record the start and end time for each rendered frame.
If you want to test different render settings, you’ll have to save the files seperately with the particular settings, as there is no command line options for changing render settings other than the output file type.
You also mentioned the term “batch”. I don’t know if you’re aware of .bat / .cmd files (Windows) or shell scripts (Linux). On Windows you’d put the above commands in a .bat or .cmd file then run it from the command line. In Linux no particular extension is necessary, buy you have to make the file executable with chmod. …Sorry if you already knew that 
Mike
Thank you for your help. This weekend I’m going to try it.