A soon to be released script for 3ds max.
It allows you to send the view of a model in you favorite painting application to paint your textures then project it back on your model.
You have the benefit of working in your familiar painting environment with your favorite brushes at the speed you are used to.
Don't have to fear ruining your existing texture by projecting on a new layer and have the ability to edit, move and do anything you want with the projected paint.
The very good representation of your shading, lighting and normal map in in your painting application will help you paint more accurately, no more guess work.
You can paint on any map, diffuse, specular, bump, opacity etc.
Indestructible workflow by projecting on a new layer:
[ame="
http://www.youtube.com/watch?v=irftZZx-FKo"]Projection Painting with layer support - YouTube[/ame]
Using a photo as texture:
[ame="
http://www.youtube.com/watch?v=5IxTfLJH4OA"]Projection Painting with Photoshop's Puppet Warp - YouTube[/ame]
Painting diffuse and opacity:
[ame="
http://www.youtube.com/watch?v=hpVymTNzTMI&feature=mfu_in_order&list=UL"]Projection Painting Preview - YouTube[/ame]