From ZBrush to XSI
Once I'd finished the ZBrush sculpt, I could then start extracting the normal map, using Zmapper, and the displacement map using Displacement Exporter. You can search the ZBrush website for a guide to using these tools - you will find it quite informative and detailed! I used a new low poly mesh that I modified from ZBrush, replacing the old low poly mesh. The reason for this was that, with the more accurate low poly silhouette, I could gain more accurate displacement and normal map renders. When I was applying both the normal map and displacement map, I always made sure to use tangent (Properties > Tangent) in the object properties, and I also made sure not to forget to freeze the model after applying tangent (Fig.06).
With regards to displacement (Fig.07), I made a way to optimise the displacement render. (My friend helped me to create a tutorial for this - the video can be found on his website at: http://darkvertex.com/tutorials/fasterdisplacement/). Depending on your object size, max disp. may vary; don't hesitate to test the numbers for something more than 10 - use your artistic eye! If it appears to be "blobby" then it means you've used way too much; if you don't see anything in the render then that means it's too low! We can see the rendering results in Fig.08.
Because I followed the previous steps in a specific order, I had the advantage at this stage. I was actually able to recycle the normal map that I created (or displacement), to create the colour map and specular map - and I could even correct/add more detail in the normal map itself (Fig.09)! With crazy bump, you can easily convert the normal map into a high frequency diffuse map (Fig.10). I used this map in Photoshop as an overlay layer, enabling me to get instant details. I always make sure my Photoshop layers are organised into groups, as this makes it easier for me to make changes or to add additional paint. I also use a Photoshop file for each material (Fig.11, Fig.12, Fig.13, Fig.14 & Fig.15).