Figure 5

However, at this point, I did find one problem. Remember I said I was wrong before. I thought both models' UVs would be the same, but I really didn�t foresee what would happen here: The high-poly model had more points along the UV boards, thus its UV boards were rounder than those of the low one. That meant seams would happen on those board area. Figure 6 shows the problem.

Figure 6

What were the solutions?

• Solution 1: Use the low-poly models� UV as a guide, and move the high one�s to make them match. In Maya, it could be achived via snap tools, I am not sure the way in other software package. However, it is time consuming and it is not fun. Most 3D people do their jobs because it's fun to work on all kinds of stuffs. Unfortunately, I can't see that sitting there and moving hundreds of UV points will make people exciting.
  
  
• Solution 2: Generate the normal maps first; assign them as color map to the low-poly mesh, and use 3D paint tools to manually paint away the seams. This might be a good solution, but it still has its limitation. For example, if you arrange UVs into two squares in Maya, then you can't use its 3D paint tools to blend colors between two maps (if I am wrong, please point out). I am not sure about other 3D paint tools such as deep paint 3d and body paint since I never used them before. Overall, solution two is better than the solution one.