Engine Repair: Eevee and Substance Designer Workflow

Introduction

My name is John Dupuis, I am currently a freelance artist with several years experience, I have no background in AAA development yet, but I did work as an Environment Artist at Quantum Integrity on the indie project Dead Matter, which I highly recommend you check out.

About the Project

The goal of this piece was to take existing work I had done on a project for Interplay Learning, a Training Simulation company. Around this time, I made the decision to move to Blender to handle all modeling aspects of the project. Upon completion, I decided that instead of publishing the finished engine model on my portfolio on its own that, I would construct a fitting environment for it and render it in Eevee. For the Diesel Engine references, I used photos taken on-site for the project. This was a very difficult prop, so organization and laying out each section was extremely important. The model is a Caterpillar C13 Diesel Engine.

I used hardly any references for the environment, after blocking in the shapes, I wanted to see how far I could take this environment by following my mind’s eye and modeling the props to match. As a result, all the unique pieces came from modeling individual assets in my spare time. For inspiration, I was playing a lot of CONTROL by Remedy Entertainment around the time I started blocking out the environment, I loved the emphasis of (mostly) grounded environments with hard surface objects, strong simplistic lighting, and subtle color correction to bring all of it together.

Modeling

As far as modeling goes, most of the assets were authored from scratch in Blender, apart from the jacket and photogrammetry pieces. Each asset was blocked out in Blender, polished in ZBrush and brought back into Blender for the low-poly retopo/UV. The jacket was produced in Marvelous Designer using a basic design and was brought back into Blender for the retopo stage. The blockout of the engine was made easy through Blender’s modifier-based non-destructive workflow. I used the HardOps add-on, as well as the free machin3tools add-on to speed up my workflow and to help achieve quick results when constructing all the props present in the scene. This setup tends to favor a hard-surface workflow, but these tools are generally useful for any modifier-based workflow.

After I felt satisfied with the forms, I triangulated them and sent them to ZBrush and used the dynamesh + polish workflow on the Boolean pieces to get the result I was after. The retopo took place in Blender using basic modeling operations, the Shrinkwrap modifier on the decimated high-poly proved very useful for retopo, and I rarely ever had to fight with it to get the result I wanted. I also used the Weighted Normal modifier often to control smooth shading behavior and bake cleaner normal maps. While Eevee itself is not a game engine, I still wanted to produce game-ready optimizations as I enjoy the challenge of making my scenes perform well in real-time. The entire scene is only 500k tris.

The exterior portion largely consists of sculpted terrain, a few unique props, and some old photogrammetry work I did use Agisoft Metashape, ZBrush for scan cleanup, and Substance Designer for baking and removing light from the diffuse.

Texturing

Most of the props were made through simple materials, I rarely ever had to resort to anything beyond a simple base color, some procedural noise/grunge to bring out the roughness and height values. After that, I would add minor details to bring out the grunge/wear of the material using baked information as a base (AO, curvature, world space normal, etc.).

For increased efficiency, I took advantage of the smart material system to quickly add my own effects on top of the textured pieces, effects such as a coating of dust on the tops of surfaces, some slight discoloration of the edges, and some added roughness in the AO, and subtle oil stains. I also added paint a paint layer at the top of the stack to paint in the finishing touches. I also have a library composed of Substance Source and Quixel Megascans materials to choose from, which I used for general texturing purposes and terrain materials. Substance Designer played a role in creating the tarp material. The model of which is just a simple cloth simulation with added touches like the metal rings baked in painter.

Substance Designer also played a huge role in producing dirt build-up in the corners and against the walls of the warehouse. For this, I used a simple Megascans dirt material, and I overlay the height information of the material with a blurred SVG to paint in the shape of the decal I wanted. Then by playing with the values inside the height blend node, I would get a very straightforward decal sheet in order to dirty up the space.

Generally, Substance Designer played a huge role in all aspects of the project, whether it was generating masks for the rust drips, the garage door, the workplace safety signs, the muddy treads, and all clutter essentially. It’s an indispensable tool for any environment artist.

On Eevee Engine and Lighting

There is one major advantage to working with Blender’s Eevee and that is the ability to visualize your changes live in your 3D viewport without the need to export and link materials in another engine. You have a great degree of flexibility and control using Blender’s material system and animation tools, in addition to real-time PBR shaders without ever leaving the editor.

A good demonstration of the flexibility Eevee offers is in the vertex paint assisted material-effects (rusted walls, puddles, terrain blending, etc.), Irradiance Cache (indirect lighting probes), and the non-uniform density in the volumetric fog. The material editor is an extremely powerful tool, here are some example uses of the material editor I employed in this project.

Regarding the lighting, it was extremely easy to set up, I used area lights for subtle ambient lighting in the windows and doors, I used directional sunlight that was lined up with the HDRI map in the environment, and I added a handful of extra lights that don’t cast shadows to bring out more ambiance.

I hope you found this breakdown informative, Blender is in an interesting place right now, and I see a lot of artists moving towards a software agnostic workflow. It will be interesting to see what the future holds for this wonderful piece of software. Thanks for reading, and I hope you learned something!

John Dupuis, 3D Environment Artist 

Interview conducted by Arti Sergeev