Optimize 3d Models for Strategy Games with Simplygon

Strategy games, especially real-time strategy (RTS) titles, often feature large maps filled with numerous units and structures. The maps are dynamic and can change based on player actions, such as terrain destruction or aggressive resource gathering. The number of units on screen can vary greatly—from a handful to hundreds or even thousands during large battles. You also can't really control if the player decides to spend all population points on a massive peasant army. The camera is often top down, but players can zoom in and out to inspect specific units or areas.

Overall, this makes strategy games a unique challenge when it comes to asset optimization. In this blog we’ll share tools and techniques that are especially useful for optimizing strategy games.

Low poly triangle reduction for buildings and units

For general asset optimization, Simplygon's Triangle Reducer is a great starting point. It can significantly reduce triangle count while preserving visual fidelity—ideal for strategy games where many assets are displayed simultaneously. Often, assets in strategy games are already quite low poly, so we may need to bring some extra tricks to the table.

• In the blog Low-poly character optimization we learn we can often be quite aggressive with reduction targets.
• Since the camera is frequently top down we can use visibility settings to optimize the model more aggressively from angles that are rarely seen. Explained in Visibility culling and weighting with sphere and hemisphere.

To prevent meshes from falling apart at very low triangle counts, we can use vertex welding and Tjunction removal to make the mesh more connected. Covered in Geometry Importance and Welding for low poly optimization.

Switch to remeshed proxy models for very low poly targets

For very low triangle targets, triangle reduction alone is often not enough; the model can break apart into a “triangle soup.” For such cases, very low poly proxy models can be created with Simplygon's Remesher.

This works for buildings, vehicles, some environment assets, and even skinned characters. Replacing the last step of an LOD chain with a remeshed proxy model optimizes the asset by:

• Reducing the number of tiny triangles
• Minimizing overdraw
• Consolidating into a single draw call

This is essential for strategy games where many units are visible simultaneously when the camera is zoomed out.

Strategy games often feature units with colorable parts (e.g., player colors). Depending on how those parts are marked in the original model, different options exist when creating remeshed proxies:

• If colorable parts are marked with a texture mask, that mask can be cast to the proxy model alongside other texture channels like albedo, normals, and roughness. Example: Load additional texture channels into a Simplygon scene
• If colorable parts are separated by material, use Geometry Data Casters to cast material IDs to a texture in the the proxy model's UV space. With that information you can determine which proxy regions should be colorable.

If it's not possible (or desirable) to use different materials for different LOD models in your engine—and you want to avoid extra material cost—you can embed the baked proxy texture into unused space in the original texture. Example: How to merge proxy texture into original texture map.

What tools are suitable for vegetation optimization in strategy games?

Vegetation assets can be tricky to push to very low triangle counts. For LOD levels closer to the camera, Simplygon's Triangle Reducer works well. For very low triangle targets, switch to Billboard Cloud for vegetation. With these two tools you can cover most distances vegetation is seen at in strategy games.

In strategy games we often view the world from above when zoomed out. This means we must be mindful of how assets are optimized for that perspective. Flipbook is not suitable here since it is designed for side viewing. The same goes for vegetation Billboard Cloud with FavorVerticalPlanes enabled.

Billboard Cloud proxies for architecture made of thin geometry

Strategy games also contain manmade objects with thin geometry like fences, steel frameworks, wooden beam structures, and other loosely connected assets. Like vegetation, these are difficult to optimize at distance with only triangle reduction or remeshing. For these assets we suggest using Billboard Cloud: Outer Shell. That tool creates a proxy consisting of billboards that preserve the outer shell of the asset.

Where to start with optimizing assets for strategy games?

When evaluating if automatic asset optimization is suitable for your project there are two things to investigate: (1) whether optimizing the models solves your performance issues, and (2) whether the quality of the optimized models is acceptable.

A suggested workflow:

1. Aggressively optimize all models with triangle reduction to see if performance targets can be met.
2. Expand to include proxies such as remeshed models or Billboard Clouds to realize full potential.
3. Once target performance is reached, iterate on quality/performance balance.

• If your game is built in Unreal Engine or Unity, Simplygon has plugins that make integration straightforward.
• For a custom engine, the easiest starting point is to use an intermediary file format like FBX, USD, or OBJ between your engine and Simplygon.

With custom engines, you often want to ultimately integrate Simplygon directly with your internal data format. This lets you avoid limitations of interchange formats and gives full control over import/export. You can do this by writing a custom importer or exporter using Simplygon's Scene Graph API.