Xiahou Ba Progression - Difference Between Baking Normal Maps in ZBrush & Maya

While I continue to develop my rendition of Xiahou Ba from Dynasty Warriors 7/8, I have been running some tests with the texture data I'm getting back from the high resolution sculpt in ZBrush. The UVs are holding up very well which I am pleased with, but I noticed some of his normal maps have a little to be desired still; they often seemed a bit faint or flat in areas, compared with the true 3D sculpture.

Looking into this problem online for a while, I started reading posts from people saying ZBrushs' normal map baking is very weak and they don't even use it for this reason. Instead, they use their original 3rd-party application for this job, such as Maya, Modo, Max, or XSI.

(Softimage XSI no longer exists as of 2015 by the way)

With this idea, I decided to bring a high resolution mesh from ZBrush (Sub-division Level 5) into Maya, along with its 'game-ready' counterpart. I then used Maya's 'Transfer Maps' tools under its 'Rendering' tool-set to bake the surface information from the high resolution mesh to the low resolution mesh in the form of a normal map. The results certainly are different, and it does seem Maya does produce slightly superior results:

This GIF animation shows the actual difference between the bake from ZBrush, compared with the bake from Maya. The frames are spaced 2 seconds apart, so give it time.

To accompany this, I will provide you with the high resolution bakes themselves. The top image shows the results split next to eachother, and the bottom images show the full results side-by-side.

From studying the differences between the two map bakes, both completely unadulterated, you can make some general observations straight off the bat:

• Maya's bake contains stronger reds and greens, increasing the overall intensity of the normal map compared to that from ZBrush.
• ZBrush by enlarge has a cleaner resulting map straight away, with less tangent distortion around the neck and bottom of the torso on the map. However it is important to point out at this stage that Maya can fix these issues with tweaking of its options; it is simply the case that ZBrush appears to be more optimised for this kind of work from the get-go.
• ZBrush appears to have possibly distorted the baked results very slightly, most noticeable on these bakes around the nipples and under the arms. Despite saying that however, I'm still not 100% sure it really is distortion, and it could be Maya that has distorted the results instead and that they simply just look a bit better. This would all be down to the target search area set up in each software package accordingly.

In other words, it might be that Maya produces better, stronger results overall, but they require more tweaking around the edges and more tweaking of the options before each bake than ZBrush. It would theoretically be possible to also intensify and adjust the normal map bakes from ZBrush to get better results also, however this process can be very difficult to do without breaking the continuity of the maps (seams can suddenly become violently visible if you simply increase the contrast on the maps).

These GIF animations shows the results working on the actual model. Especially pronounced on the greyscale images, you can see that the baked map from Maya gives a much greater sense of 3D than that from ZBrush.

I would not call this testing conclusive. While Maya holds better results than ZBrush for this model, the same might not be true for other models. Also remember that both of these maps are made using somewhat standard settings in both applications, and so further tweaking of the options may produce better results and worse results in both software packages respectively. However the issue with ZBrush baking normal maps to look much flatter and less intensive is something that has no options to modify. For this reason alone, I think further testing with Maya might hold better results for my future projects.