This is a tutorial that shows you how you can use a high polygon model to create texture maps for a low polygon model. Since creating planar maps are simple and straightforward, it will focus on the more difficult method of creating spherical or cylindrical maps. This is not a step by step tuturial, you should have some basic knowledge of 3DS Max, and low polygon modelling. We will focus on two techniques, the first being easier and quicker than the last. As our example, we will use a tie fighter, and we will focus on building a texture map for the spherical hull.
Lighting:First set up the lighting so that it will be consistent throughout all tex maps.Increase the ambient light to 50,50,50.Create a sky light, change the color to white, and turn on shadows.
Render the model and make any adjustments until the surface tone is correct, and the details are visible. Since the tie fighter will be turning upside down, you want the entire model to have a nice even lighting. Avoid creating a shadow on the underside of the object.
The next thing to do is prepare your model. Isolate the parts that will be mapped onto a low poly sphere, then attach them, so that you end up with a single object.
Collapse the modifier stack, and add a UVW modifier. Make is a spherical map.Adjust the gizmo, so that the polar regions are in an area that will not show as much. Maps tend to get distorted in this area. Luckily, the tie fighter has natural breaks (windshield, and backlight), so this is the best place to put the polar axis.
If you are having problems with your UVW gizmo, you should do a Reset Xform (utilities > reset xform).
Select the object, then go to Render to Texture.In the general settings rollout - Change the path to your project folder.
In the output rollout -Click the add button.Add a complete map. Change the size to 512 x 512 (or higher if needed)
NOTE: If you are having problems with the render output, getting strange artifacts, such as missing polygons, or uneven shadows, click on the setup button under the general settings rollout. Go to advance lighting tab, and select Light Tracer.
IMPORTANT: Check the far edges of the map to make sure there are no missing polygons. If you see any blank spaces, you may need to rotate the gizmo to find a natural seam. You can check if there are any stray polygons by adding an unwrap modifier. It will show any polygons that are moving outside the texture area.
You will notice in the rendered texture that there are some strange artifacts. Unfortunately, this is not acceptable. If your texture came out beautifully, then consider yourself lucky.
If this technique doesn't work, then you'll have to do it the hard way. To learn the alternate method, go to the cylindrical render tutorial.