2D vector file formats have advantages over bitmap image export in that they produce drawings that are resolution independent and can be easily imported and modified in many other programs. These file formats are useful for creating a set of 2D construction documents, plotting a perspective in a large format, or for import into vector illustration software for further refinement.
Encapsulated PostScript format is based on PostScript, a graphics description language developed by Adobe as a standard way for graphics programs and print devices to communicate. EPS is widely used in the graphic design and publishing industries.
Adobe┬« Portable Document Format (PDF) is the open standard for worldwide electronic document distribution. PDF preserves all the fonts, formatting, graphics, and color of the source document, regardless of the application and platform used to create the document. Also, PDF files are compact and can be shared, viewed, navigated, and printed exactly as intended by anyone with free Adobe Acrobat┬« Reader┬« software.
DWG (AutoCAD Drawing File)
DWG was created by AutoDesk as the file format for their AutoCAD program. There are many different versions of DWG, including DWG r12, r2000, and r2004.
DXF (Data Exchange File)
DXF is a 2D graphics file format supported by most all Macintosh and PC-based CAD applications. DXF was created by AutoDesk as the method for exchanging CAD data between their AutoCAD application and other CAD applications.
The Anatomy of an Epix File
The native file format of Piranesi is referred to as an Epix (Extended Pixel) file. In addition to storing the actual rendered image, Epix embed additional information from the original 3D model. This information allows Piranesi's paint tools to intelligently render the image. There are three 'channels' of an Epix file:
The first, known as the RGB Channel, contains the color of each pixel. This is the same data typically stored in other raster image formats. (In fact, Epix files are readable in most image editors as TIFF files.)
The second, known as the Depth Channel, stores the distance of each pixel from the eye point. This information helps Piranesi understand the surface topology under the image and allows it to apply textures, scale objects, lock orientation, and many other capabilities dependent on the 3D surfaces of your model.
The third, a Material Channel stores the material for each pixel. This lets you paint one part of your rendering loosely without having to worry about painting another by mistake.
In General, Piranesi expects a flat shaded, non-textured Epix file. Some of the rendering modes in SketchUp, such as Wireframe and Hidden Line, don't really work well for Piranesi and are disabled during export in favor of shaded output.
Other features of SketchUp, such as edges and textures, are also different from that which Piranesi expects, yet may be desirable in many cases. While adding support for Epix files in SketchUp, we have tried to adhere to Piranesi's expectations whenever possible while retaining enough flexibility to accommodate the varying needs of different artists and renderers.