Render Test: Part 2 - The Investigationing
If you missed Issue 1, hit the 'Older Post' link at the bottom right!
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Everything except the base (I find it easier to do basic shapes like that in Maya) was modeled and textured in ZBrush. The Maya version uses normal and displacement maps, and AO was added directly to the diffuse. I typically use xNormal to bake all these.
The render from ZBrush had some comp work done in PS - AO, shadows and cavity maps.
Things did not match up as well this time.
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The top image was done in ZBrush, the bottom one rendered with MentalRay in Maya.
Yikes. Where to begin? Both images have their strong and weak points. Here's a split image for your convenience:
Skip to the bottom for a quick list of future plans, carry on reading for long-winded drivel!
The lighting in the Maya render is by far superior; you can even tell by looking at the thumbnails. I've never seen surface detail show up like that in ZBrush before. It lacks the shadow cast by the stump though, I just couldn't get it to show up clearly.
Model-wise, the ones in Maya came out... puffy. The rocks look like grey marshmallows with a touch of mold, and the vines are too smooth. A substantial amount of detail was lost on the tree - check out the knot and the area around it. All this is easily attributed to my incompetence though. I rely on UV Master to unwrap models, and this time it's likely to have botched my shot at a decent displacement map. The difference between one of the maps from this project and the plank is enormous. I tweaked it in Maya as best I could, but it was nowhere near enough. The rock models are pretty boring in general, I'll need to do more of those.
Strangely enough, the grass looks sparser in the Maya render. I wanted everything to be the same, so I couldn't use FiberMesh in ZBrush (you can't directly convert them to polys, according to my research). It also ruled out the use of Paint Effects within Maya. I could create grass and turn them into polygons effortlessly, but I couldn't find anything on how to export a texture map based on the settings used. Unwrapping would have sucked, too. I'm certain that workarounds exist, but I failed to find any at the time.
So I did what I had to do, and made the grass from scratch. I used 20 strands of grass to make 3 different clumps, and duplicated them around in my ZBrush scene until it was decently populated. My friend also reminded me about the specularity of grass. I had completely forgot about it, and had already moved on.
By that token, I realized that I don't mess around much with materials in ZBrush. I generally use basic ones, maybe even a quad shader for larger projects. For the most part, I don't know what I'm doing. Ditto using mia_material_x in Maya; I just follow other people's settings.
Last part of this dissection is textures. Still bland in ZBrush, still bland in Maya. Bland city. Just looks nicer, thanks to the lighting. From the beginning, I've poly painted every single model I've made. The resolution of the texture is dependent on the poly count; the more polys you have, the higher the res of the texture. I typically have my models at a max of 2-3 million points, and fine detail comes out blurry at that level. I believed that it would only make a difference when you're zoomed all the way in to the model. Now, I'm not so sure.
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One cannot fault ZBrush for having poorer render capabilities when one's a noob.
Here's a summary of what I think needs to be done:
1. Paint textures in Photoshop, very much like real 3d artists do.
2. Unwrap models better (typically I define a few seams and let UV Master do the rest). Ties in well with the previous point and would hopefully result in better displacement maps, too.
3. I need to consider the use of specific materials and their settings. More so in ZBrush.
4. My lighting process in ZBrush also requires greater scrutiny. I'm going to try out LightCap or HDRI lighting for more sophisticated results.
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