Wednesday, 29 October 2014

ZBrush; my favourite worst enemy

So we've divided up our assets and I was allocated the stool, misc silver and cups because I was the only member of our group familiar enough with zbrush to tackle the cup designs, which we knew early, would definitely need to be sculpted.
I started with the basic cups at 300 triangles each (I used 252) to make each of the basic shapes. One was slightly higher and had a larger rim but aside from that they were very similar, but the slight difference is shape made a nice difference considering how many time the cups would be instanced and repeated around the room.

My next task was to sculpt the detail into the cups, I had a very limited experience with zbrush prior to this so I was slightly apprehensive but once I started I found myself enjoying the more authentic ‘modeling’ feel to it. It was far easier to creature the curves and grooves this way than in a normal map. Unfortunately while the zbrush object itself was overall successful, I had a huge amount of trouble high poly baking it because of some things I failed to prepare and anticipate I needed in the 3ds Max file.

We decided we were going to conserve texture space and combine the cups, ketchup, salt and pepper, table, scones and plate were not slated to share the same space. Unfortunately because I’d already unwrapped and sculpted based on that unwrap, it was now unusable. There were also some problem with the bake itself as the cup was not centered to the world when it was exported as on object (I thought I could move the bake once it was in the scene- but it doesn’t’ work that way) so I needed make sure for cup was in the exact correct final position before I took I into zbrush.  I also had a problem with dividing the geometry in zbrush completely obliterated my corners and made the edges and rims smooth- so when I went to mask out the top and bottom, I didn’t realize I was missing one of the edges because it had been totally smoothed out. The mask was also a bit rough as you can see because some of the pattern goes over where it shouldn’t.  So for these reasons the first iteration of the cup didn’t work.  Too help with the dividing I tried turbosmoothing the mesh before exporting, this helped with the divide itself and everything kept it’s angles, however it made the high poly bake process very tricky, I also couldn’t quite get the pattern the same and zbrush consistently crashed so eventually I decided to just export it as a normal map and just copy it into height map. This gave me the exact pattern I wanted from the original try and also allowed me to completely and cleanly keep my angles by editing where the lines ended and began on photoshop. The overall effect is incredibly similar to what a high poly bake would have achieved but was far better to handle.
  I tried to do a similar process with the second cup but this time I realized that because unlike the prior, this pattern was repeating and need to be even and equal, that it would be more appropriate to do it with the standard height map. This yielded a much crisper result and I now know where the use of zbrush is more appropriate.

Texturing the cup was frustrating, because the actual reference has absolutely no roughness or texture detail, I constantly tried to fight the urge to over complicate the design, often I added to many roughness details and had to backtrack because it simply didn’t match the image. Even if the end result looked good. A few iterations in I found a good balance in detail and just let my normal map be the prime decoration of the cup- just like in the shot. Although a higher resolution picture would have been a great aide. 

No comments:

Post a Comment