Alchemy isn’t software for creating finished artwork, but rather a sketching environment that focuses on the absolute initial stage of the creation process. Intentionally reduced to a level of functionality there are no undo, no selecting, and no editing features. Interaction focuses instead on the output of a great number of good, bad, strange and beautiful shapes.
Alchemy is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation. A download is available for Mac 10.5, 10.6, Linux and Windows
A quick demo showing how an Alchemy sketch can be used inside ZBrush. Using the Alchemy sketch as an alpha mask, flat shapes are explored in 3d for a helmet or mech head concept piece. al.chemy.org