Environment Design in Drop Assault

staff_cory_chatwellI’m Cory Chatwell, 3D Team Lead on Horus Heresy: Drop Assault. As team lead my job is to listen to every department on the project. I sit down with designers, programmers and artists and gather all the goals and restrictions from the team and then try to find ways to satisfy all of these requirements while maintaining a balance between visual fidelity and performance.

Target Goals

The bulk of my input on a project is in the early planning stages. I wanted to share with our fans how we’ve gone about doing environment planning and map design.

The environments in The Horus Heresy: Drop Assault had to have depth. Going for a 3D approach with the environments (versus 2D like the unit sprites) allowed us to create a parallax effect and give players the feeling that they’re really interacting with the world.

We needed…

  • A building system to accommodate any number of map layouts
  • A variety of geographical regions to be represented
  • To capture the look and feel of a post-apocalyptic, recently virus-bombed Istvaan III
  • It to feel as intricate and detailed as the rest of the Warhammer Universe
  • And it had to look and run great on relatively low power devices like the iPhone 4.

It was clear early on that we would need a systematic approach for the majority of maps, a system that still held up visually and allowed the flexibility needed for designers to create their vision.



Each map consists of two regions: the playable area in the centre that needed to remain relatively flat and clear of obstacles to allow for the custom placement of defenses and troops, and the surrounding environment frame. The playable area was a challenge in that we needed the ability to make as many playable area layouts as the designers could dream up. We ended up creating a series of sixteen tile shapes as well as a map layout tool that would allow the map designer to place, rotate, flip and align tiles and defensive structures however they saw fit. Along the way designers would sometimes request unique pieces or additional elements to further flesh out the maps. Using a tile system meant it was simple to incorporate new elements along the way. Creating a quick and easy system for map design was a real focus in the early stages of development. Developing the tools and the process early on was key to producing the amount of content that we have.

The next step was the creation of the environment frames. While the playable areas were built systematically using tiles, the frames were all completely custom. We based the look of Istvaan III off established lore and conceptual art, drawing influence from the Horus Heresy books and the available kits from Games Workshop. These frames contain the rich details that flesh out the world: mountains, rivers, cathedrals, towering bridges, statues and more. The goal here was to match the already established architecture and visual design of the Warhammer universe and make the maps feel grounded in the world of Istvaan III. Fans of Warhammer will no doubt recognize the iconic gothic spires and steel plated fortifications from the “Wall of Martyrs” or “Fortress of Redemption” kits, and many others were directly referenced.  After recreating many of these elements in 3D, we had a lot of fun kit bashing and destroying them to create environments that we found would best represent the virus bombed surface of Istvaan III.  The player’s base is nestled in the remains of a shelled keep atop a cliff. This gives the player a sense of safety in their own fortress, while still conveying the apocalypse that has ravaged the old ruin. When the player ventures outside these walls they are met with fierce battles across the desert remains of urban centers, as well as more rural industrial areas, mining complexes and mountain ranges.

Another challenge that we faced was the technical restrictions on map size. In order for units to know where they could and could not walk and how to get where they were going, the map creation tool had to generate a “navigation mesh” based on the tile layout. These navigation maps could only be so large before they started to bog down performance on devices. Sometimes limitations can actually be helpful. In this case it allowed us to create environment frames that fit all sizes of map by modeling them at our maximum navigation mesh size. We created the foreground and background as separate sliding interlocking pieces, from there all we had to do was drop in the playable area and adjust the frame to match.

Working on the battle environments for Drop Assault has been a really fun and exciting challenge for us. We can’t wait to show you what else we have in store for the Horus Heresy: Drop Assault, so stay tuned for updates.