Choose a method for optimizing draw calls

Use draw call optimization if the CPU sends too many draw calls to the GPU, which is also known as being CPU-bound. For more information about draw calls, refer to Introduction to optimizing draw calls.

Check the number of draw calls

To check if your scene sends too many draw calls, do any of the following:

• Open the Rendering Statistics window and check the Set Pass calls value.
• Open the ProfilerA window that helps you to optimize your game. It shows how much time is spent in the various areas of your game. For example, it can report the percentage of time spent rendering, animating, or in your game logic. More info
  See in Glossary and select the Rendering section to display the number of draw calls.
• Check the number of draw calls in the Frame Debugger.

Choose optimization methods

The supported and recommended methods for optimizing draw calls depend on whether you use the Universal Render Pipeline (URP), the High Definition Render Pipeline (HDRP), or the Built-In Render Pipeline.

If you have many instances or lights, you can also use optimize mesh rendering using level of detail (LOD).

To get the best results from any draw call optimization method, do the following:

• Use the same materials for different GameObjects as much as possible.
• If you want to render the same mesh with different properties, for example different colors, use Material Variants instead of multiple materials.
• Avoid using the MaterialPropertyBlock API in URP and HDRP.

Use multiple optimization methods

You can use multiple draw call optimization methods in the same scene, but each GameObject uses only some methods depending on its mesh and shader.

If you enable all the features in the table, Unity does the following:

• Static meshes: combines the meshes with static batching.
• Dynamic meshes with a compatible shader: uses the SRP Batcher with the GPU Resident Drawer or the BRG API.
• Remaining meshes with a compatible shader: uses GPU Instancing.

Additional resources

• Shader variantsA verion of a shader program that Unity generates according to a specific combination of shader keywords and their status. A Shader object can contain multiple shader variants. More info
  See in Glossary
• Fantasy Kingdom in Unity 6, which uses the GPU Resident Drawer.
• SRP Batcher: Speed up your rendering
• BatchRendererGroup sample: Achieve high frame rate even on budget devices
• Megacity Metro, which uses the BatchRendererGroup API to render a large number of objects.