I recognize this is not directly what the topic was about, but it's tangentially related enough to possibly be useful to some readers.
A lot of folks in the 3D printing community make 3D lithophanes (
http://www.vectric.com/products/pvc/features/3d-lithophane.html) from standard photographs. A lithophane converts value (light/dark) to height.
There is a tool on Thingiverse (
http://www.thingiverse.com/apps/customizer/run?code=7d14b4631fe1e9a942dea9386939d6e7) that will make an STL from a photo. There is a free tool (challenging UI, but very configurable,) called BMP2IGES (translated page
http://translate.google.com/translate?hl=en&sl=de&u=http://geisel.ba-bautzen.de/bmp2iges.htm&prev=search).
Both of these will create STL files (most common 3D printing model format,) and it looks like PartWorks3D will ingest these happily.
123D Catch takes some patience, but can produce amazing models. They are not always manifold (
http://airwolf3d.com/wiki/manifolded-edges-how-to-check-if-your-model-is-watertight-and-ready-to-3d-print/ ). But this can frequently be fixed with the indispensible free version of Netfabb Basic (
http://www.netfabb.com/basic.php)