Next are some hints about how to use the Normal Map Filter in Photoshop. Â The settings explained here refer to the next image.
1. "Invert Y" is necessary so that the normal map will be correctly displayed in Maya using the default settings.
2. The recommended methods of generation are "Average RGB" or "Colorspace".
3. Experiment with the Scale value to obtain the desired depth for the resulting normal map.
This filter has its limitations in the fact that the resulting normal map lacks depth, because there is almost no information saved on the depth (blue) channel of the normal map.
When added depth is necessary, or the source image is not a height map but a fully lit colour texture, like a picture, the program to use is Crazy Bump http://www.crazybump.com/
As an example, this is how the tyre normal map was created. The base image is this one:
I used Crazy Bump 8.6 Beta which has separate buttons for opening height maps, pictures or normal maps as sources. Â In this case I used "Open photograph from file". Â Just as the Normal Map Filter, this program requires some experimentation to better understand how it works. Â To make it easier, these are the settings used to generate the tire texture:
The resulting normal map from these programs can be added on top of the normal maps previously generated by using Overlay. More than that, Crazy Bump can also generate an ambient occlusion map, so that can be used also to enhance the colour texture. This isn't the case here as the source picture has enough detail to be added to the texture as is.
Finally, here are some screenshots of the final work done in Maya using High Quality Rendering.
I hope this tutorial was enjoyable to read and that the information in it is useful for you. Â The pipeline described here is a very good indication of what is required for a 3d artist to accomplish while working for a Next Gen game, and hopefully this will help answer some of the questions people ask when trying to find out more about how in-game cars are made.
About the Author:
Valentin Nadolu is Lead Vehicle Artist at AMC Studio since 2006. Â He is a physics engineering student at the Faculty of Electronics, part of the University Politehnica of Bucharest. Â He and his team have done vehicle work for such games as Test Drive Unlimited, Mercenaries 2, Saboteur and a yet unannounced Blackrock Studios (a part of Disney's Interactive Studios) title.