Thanks a lot for sharing! It's hard to find useful info on lighting.
Wow, that's great. Have to try this out!
3d artist Tyler Smith did a detailed breakdown of the ground material, created with the help of World Machine, Quixel SUITE and Zbrush.
My name is Tyler Smith and I make game environments for a living! I am currently working out of Denver Colorado as a senior environment artist at IllFonic. My daily work consists of creating environment assets and technical problem solving to get the best results in game! Right now the biggest project we are working on is the Friday the 13th licensed game.
For the ground demo I wanted to focus on the material difference between the sand and the rock as well as the relationship between the sand and rock and how they interact with each other. How sediment flows and collects around objects stuck in it and how rocks in the ground are effected by wind and water in a different way than rocks on a cliff or gathered in an outcropping.
Mixing World Machine and GeoGlyph
For World Machine and GeoGlyph when I’m doing ground textures I always use this software because of the mind blowing erosion and sediment flow algorithms that were made by these talented people. One thing I always have to keep I mind is World Machine is made for creating assets that are square kilometers in diameter. So making sure the sediment flow created has an essence to it where it could pass as a sediment flow of a river bank rather than a mountain side. For rock work in the sediment I prefer to create all rocks in ZBrush and place them into the sediment in order to have complete control.
Building the Terrain
One thing I keep in mind is that the sediment flow created in World Machine always starts as the base and I then add sculpting detail and additional texture overlays on top to marry the two aspects of sediment scale together. One other aspect to keep in mind is to export the color information based on the erosion channels and sediment collection. In order to make this clear it’s best to have the sediment flow be a different value and color to the non-eroded sediment.
Adjusting in Zbrush
When I import the mesh form World Machine into Zbrush I then start placing the rocks in accordingly, making sure they are arranged in a way that will tile easier when the tiling filter is applied in Photoshop. To make the rocks I take alphas generated from Zbrush scene captures and apply them to blank poly planes. This is important to have a unified sense of height on the final texture. One other effect I apply is around the puddles of water. To get the effect of where the water meets the sand I use a fold brush to get a form change effect I like.
What is important for Quixel is to make sure a good AO and ID map is applied. The id map will separate the rock and sediment. When working in Quixel the other major factors to apply is having a sand material applied to the AO map. By doing this the hard edges between the sand and the rock are softened out. Another major factor is roughness. The rock and sand should have a good major difference in value, then a higher contrast to establish wear and scraping on the rock surfaces.
Making sure the normal detail is sorted in the correct way is the best to avoid jarring seams between the different sculpted assets. The AO map base sand layer should have a complete opaque normal layer in Photoshop instead of the standard overlay. Another tool to use to have sand interact with the rocks better is through the real time mask painting tool in Quixel, using the mask brushes to paint the flowing sand onto the rock.
This demo took about 6 hours. It is built in a way that the values of the color, roughness, and normal detail can be modified on the fly. The Quixel file holds the freedom of changing the diffuse and roughness values on the fly. The normal values have to be rearranged in a way where a new tile normal texture has to be selected and applied to the Quixel mask.
This technique can be used in game art production. The major aspect that differs it from a substance production standpoint is hand sculpting the primary and secondary shapes in Zbrush. The only aspect that would limit the flexibility of a ground texture created in substance is the primary shapes have to be sculpted by hand and made to tile by hand in Photoshop. However this presents a workflow where artistic style and unique form freedom can be achieved with more ease.