Filter Forge is – by quite a margin – the most powerful plug-in we've looked at here. That's because it's a tool for creating plug-ins, both generative texture-creation tools and effect filters.
Filter Forge is an excellent filter creation tool with a strong community spirit that will enhance your Photoshop creations.”
“For 3D modelers, Filter Forge is a dream come true. It creates seamless textures with a single mouse click. The professional version creates the following map types for any texture: bump, normal, specular strength, specular exponent, diffuse, metallic, and alpha. The same filter can be used to generate any resolution, since filters are procedural.”