What is the difference between 'Static' and 'Dynamic' in Unity, and why is it important for lighting and batching?

• A. Static objects are not included in any rendering calculations.
• B. Static objects are included in lighting calculations and batching optimizations; dynamic objects are not.
• C. Dynamic objects always become static at runtime.
• D. Static objects cannot be moved.

Answer: (B)

marking an object as static tells Unity it won’t move or change, so the engine can invest in precomputed optimizations. This matters for lighting and rendering performance.

For lighting, static objects can participate in baked lighting and lightmap generation. The light interaction gets precomputed and stored in textures, so at runtime there’s no heavy real-time calculation for those objects. Dynamic objects, by contrast, aren’t baked into those lightmaps unless they’re marked or treated specially (for example, via light probes or real-time lighting), so they’re lit differently and with more runtime cost if you rely on real-time lights.

For batching, static objects can use static batching, which combines their geometry to reduce draw calls, since they don’t move. That lowers CPU work and can improve frame rates in scenes with many stationary elements. Dynamic objects don’t participate in static batching; they’ll use dynamic batching or other techniques like GPU instancing if applicable, which keeps them flexible for movement but may come with different performance trade-offs.

So, static equals non-moving with baked lighting and static batching ready to optimize performance, while dynamic remains flexible for movement but isn’t included in those static optimizations.