It's a software solution many 3D printing artists have been dreaming of – the conversion of scanned drawings into three dimensional objects. Realizing that not everyone has the patience or skills to be a 3D modeler, a skilled programmer from Seattle by the name of Dylan Rush has offered up a solution. It is an application called Marble and it can turn hand-drawn sketches into computer generated geometry for 3D printing.
Rush programmed Marble to create octrees. Octrees are a file structure that can efficiently store 3D data. Think of an octree as a type of building block or cube (they are also called voxels) that can be used to represent three dimensional objects. Octrees are like scalable Legos. They come in various sizes. Smaller octree cubes help define the more detailed parts of a 3D structure.
Marble works by converting a series of scanned, monochrome drawings into the boxy octrees. To work properly, hand-drawn sketches must define the object to be printed in three dimensions (top, front, and side). The drawings must be "filled in" as well. Outlines won't work – but it would be easy enough to draw an outline, scan in those drawings, and then use the paint bucket tool in Photoshop to create solid fills.
Marble creates geometry based on the drawings and discards what is not filled in. The application goes through the process three times, rotating the geometry to match each scan that was fed into the system. The software can create geometry based on more than three scanned images if more complex geometry is desired. Dylan has also incorporated a feature that can define concave surfaces in order to make bowls and hollow objects.
Note that while some software packages have similar capabilities built in, such as ZBrush's Shadowbox, there has yet to be a standalone product like Marble that can be downloaded as a single app.
With a release date yet to be determined, Dylan is satisfied with teasing the public about his app's capability. Since the eagerness of new 3D printer owners often outpaces their desire and available time to learn the digital modeling process, one can surmise that apps like Marble will become quite popular. Visitors to his site should encourage Dylan to release the app, or at least create a Kickstarter for it. If released, Marble would be an appreciated software tool in the 3D printer community.