Although the "Vanishing Point" utility in Photoshop CS2 is not a full 3D modeler, it allows users to (among other things) create shapes that can then be exported as DXF, a CAD diagramming file format widely used by 3D artists, designers and architects worldwide in programs like AutoCad, Cinema 4D and 3DStudio Max.
Open Photoshop. Select "File" from the menu and click "Open." In the dialog box that pops up, browse to file that you have used the Vanishing Point" tool in to create "Perspective Planes" grids in. Open the file.
Open the "Vanishing Point" dialog. To do this, select "Filter" from the menu and click "Vanishing Point." The options in the dialog give you the choice of choosing to export the grids as either a 3DS file (which preserves the textures as well as the model geometric information) or as a DXF (which has only the geometry).
Click on "DXF" to choose that option. A document saving dialog box will pop up.
Name your file and choose the location that you want to save it to. Click "OK" to save the file. You should now be able to import the DXF file into any CAD or 3D modeling program for further use.