Step 4: Import the model into a rendering program
Solid modeling programs cannot render transparent objects and cannot cast shadows. Excellent results can be obtained with solid modelers, but for even more realistic images, a rendering program must be used. Rendering programs give the designer the ability to create light sources, cast shadows, apply materials to surfaces and to control the appearance of those materials, their colors, and textures.

The image now on the screen is the raw image which the program creates when the 3D wireframe (which was created in the solid modeler) is imported into it. The program arbitrarily assigns colors to objects in the sceene according to which layers they are in. The designer starts with this palette, in which all materials resemble naugahyde in various unmistakably vivid colors, and proceeds to change each material into the material intended for the final image.

Next - The Final Render