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Ehsan Ebrahimzadeh gave a talk on his WW II Trench Environment the artist generated in five days for Quixel Mixer Contest.
Ehsan Ebrahimzadeh gave a talk on his WW II Trench Environment the artist generated in five days for Quixel Mixer Contest. He shared some tips on setting up materials and dealing with vegetation.
The Idea
For this project, I wanted to challenge myself to make a small scene with a few pre-self-made and photo scanned props and foliage. The challenge is to make an environment with no new objects and only in less than a week. Thus, the goal is to have a nice-looking environment with a few objects, an optimal amount of repetitiveness, in minimum time. It’s always tricky to choose an environment, but with these restrictions, it gets even harder to have a creative and achievable scene. I had some ideas for the scene and I decided to create a WW II trench scene in the end.
Using scanned objects or textures is very common in today’s video game industry. However, personally, I always try to have some level of fantasy in my environment. I don’t like to have a %100 photorealistic looking environment which looks like an actual photo, while does not look interesting. I get inspired by nature, photos, and movies and then try to make my own version of that scene which I want it to be unique and exaggerated. I am not trying to copy the world but to translate the world into what I like to see in a video game.
I also think it’s important to reduce the gap between the scanned objects. We cannot scan everything so after all artists, needs to model and texture most of the objects in the scene. That’s where you might see some obvious difference between the scanned models and modeled ones.
Landscape
I used UE4’s terrain system. No model was created for this project as I wanted to use only scanned assets. However, I used 3Ds Max to assemble the scanned models and made a few variations of them.
Vegetation
SpeedTree is used for most of the foliage. Ground foliage like grass and ferns is made in 3Ds Max. I like working with SpeedTree since it is fast, and results can be awesome. The LOD system in the new SpeedTree 8 is really useful. I decided to use three trees and five ground foliage in the scene.
These are some questions that people asked me before: “how to make the foliage look realistic under different lighting conditions? “and “how to use scanned textures and achieve a great result??”
To answer these questions, I should say, using scanned textures really help to speed up the process; however, there are some downsides to it, such as lack of an artistic touch. Textures made in Substance Designer or models made in SpeedTree can become computer-generated generic textures and models. Thus we need to pay attention to the reference photos. We have the same issue with foliage too. There are lots of SpeedTree models, that look SpeedTree-ish, as they look so generic. To prevent this you need to study lots of reference photos. Also, don’t settle for the first results. Try to add extra details and get as close as you can to the reference photos. Foliage shader is critical to have realistic vegetation. Translucency, roughness, normal maps, and a nice wind effect can help bring the foliage to life. Lighting is also an important matter to this end.
Tile Textures
For this project, I used Quixel Mixer. Two tile textures were made: mud and jungle ground. Mixer is fast and very easy to use. It’s still in beta version but it works great. Basically, Quixel Mixer blends layers of materials (by materials I mean a full set of textures like Albedo, Roughness, Normals, and etc…) using Heightmap. They are going to add features such as blend by mask and hand-painting, but at the time I am writing this article, it is not available yet. Looking at some results with Mixer, you can see the textures can become too noisy. The noise in the texture is hard to control since these materials are all scanned and you don’t have access to the details, but it is important to tackle this matter. I always like to check my materials in a tile mode so that I can avoid any repetitiveness. You can do that by hitting “T” button on the keyboard.
Lighting
Since I didn’t want to change or make new models for this scene, lighting was very critical to achieving the quality that I had in my mind. As noted before, lighting is very important to have a realistic foliage. I tested nighttime, daytime, overcast, sunset, and etc…. In the end, I decided to go with the setup you see in the scene. I specifically chose this lighting condition because of the contrast between the cool and warm colors in the scene.
I used real-time lighting with Distance Field Ambient Occlusion and Light Propagation Volumes.
A skylight and a directional light were used for the scene lighting. Since the scene weather is rainy, the directional lights intensity is set to be very low to avoid sharp shadows.
I also used a point light with volumetric fog for the warm light colors in the trench and added one supporting spotlight to fake the bounce lights.
Exponential Height Fog can give the scene a very nice sense of depth.
Shaders
Foliage:
To make my foliage, I used SpeedTree. SpeedTree has a node in UE4 Material Editor which can be used for wind effect. It is easy to use and the results look fantastic. The wind wizard in SpeedTree is handy but I usually change the settings to get better results. Translucency is also important for natural looking foliage. You can always use a translucency map or if you restricted, use your Albedo map and multiply a color to it. The translucency colors usually need to be more saturated and brighter than the Albedo colors.
Rain Ripples:
For the rain ripples, a flip book is used and animated texture sheet is blended with water normal.
Object Placement and Design
The whole project was made in five days. I used only five Megascans assets and six modeled assets from my previous projects. The key was how I assembled the scanned objects to avoid repetitiveness. I made a few variations of the trench walls and groundwood pallets. I think composition and small scatter assets can give the viewer the fill of variation too. Using different ground foliage and scatter objects helped me a lot in this matter.