The PNG, short for Portable Network Graphics, format is used to display high-quality graphics on the Web. It surpasses the limitations of GIF files, provides greater depth of color and is free of the patent licenses associated with some popular formats. OBJ, or Object, files contain 3D geometric data. They are basically text files that contain information on a 3D image's polygons, curves and surfaces. Use Google SketchUp to convert a PNG file to a 3D OBJ file; however, if you don't add depth to the PNG file, the resulting OBJ file will look like a 2D image.
Launch a Web browser and navigate to sketchup.google.com. Click on the blue "Download Google SketchUp" button to start downloading the tool. Run the installer and follow the onscreen instructions to install the software.
Double-click the "Google SketchUp" icon to start the program. Click the "File" menu and select the "Import" option. Use the resulting file browser to find and highlight the PNG file you want to convert. Click the "Open" button to open the PNG image in Google SketchUp.
Use SketchUp's built-in set of tools to modify the PNG image. If you are an advanced user, add depth to the PNG image and make it look like a 3D image; if you don't, the new OBJ file is going to look like a 2D image.
Click the "File" menu and select the "Export" option. Google SketchUp 5 and newer versions can natively export to OBJ without using a plugin. Select "Object file (*.OBJ)" in the "File type" drop-down box. Enter a name for your new file and use the file browser to select a location where to save it.
Click the "Export" button to convert the PNG file to an OBJ file. The new OBJ file is saved to the location you specified in the Export window.