I use Blender3d to render my animation into individual images, and then ImageMagick command line tools to stitch into a sheet and set the transparent color. Here are my shell scripts that create my sprite sheets (FYI, I’m not using $4 anymore but have been too lazy to change the script :-))
Get ImageMagick here and follow the MacPorts instructions. It downloads and builds everything for you. Command line is the way to go…no point, click, drag, drop, etc. for every sprite. One command from a prompt builds all of your sprite sheets.
http://www.imagemagick.org/script/binary-releases.php#macosx
sprites:
#!/bin/sh
sprite RedGlass 32 32 1 images/RedGlass true
sprite BlueGlass 32 32 1 images/BlueGlass true
sprite GreenGlass 32 32 1 images/GreenGlass true
sprite iPhoneIcon 57 57 1 Icon
sprite iPhoneIcon 114 114 1 Icon@2x
sprite iPhoneIcon 72 72 1 Icon-72
sprite:
#!/bin/sh
montage render/$1/\*.png -tile x1 -geometry $2x$3+0+0 $5.png
if ["$6" = "true"]
then
mogrify -transparent '#000000' $5.png
fi
[import]uid: 58455 topic_id: 10889 reply_id: 40737[/import]