Developer link: http://www.glyphfx.com/overview.html
The Mattepainting Toolkit (gs_mptk) is a plugin suite for Autodesk Maya that helps artists build photorealistic 3D environments with minimal rendering overhead. It offers an extensive toolset for working with digital paintings as well as datasets sourced from photographs.
For Maya versions 2014 and 2015, version 3.0 of the toolkit adds support for Viewport 2.0, and a number of new features. http://www.glyphfx.com/features.html
1 - Unpack the release into a directory of your choice.
2 - Run the installer and install it.
3 - Generate a key for unlimited trial, but buy it if you will use it.
4 - As always, make sure to have a firewall to block outbound connections.