How can I speed-up my simulation?

[omichel]

My simulation is running slow. How can I speed it up?

[omichel]

There are several ways to increase the simulation speed:

1. Use the Run button. This button runs the simulation as fast as possible using all the available CPU power. Otherwise, using the Real-Time running mode, Webots may not be using all the available CPU power in order to obtain a simulation speed that is close to the speed of the real world's phenomena.
2. Use the Fast button. This button runs the simulation as fast as possible using all the available CPU power. In this mode the simulation speed is increased further by leaving out the graphics rendering, hence the 3d window is black.
3. Increase the value of WorldInfo.basicTimeStep. This field sets the granularity of the physics simulation. With a higher WorldInfo.basicTimeStep, the simulation becomes faster but less accurate. With a lower WorldInfo.basicTimeStep, the simulation becomes slower but more accurate. There is an additional restriction: WorldInfo.basicTimeStep must be chosen such as to be an integer divisor of the control step which is the value passed as parameter to the wb_robot_step (or equivalent) function.
4. Decrease the value of WorldInfo.FPS. This field represents the maximum rate at which the 3D display of the main windows is refreshed. With a lower value, the simulation becomes faster but more flickering. With a higher value, the simulation becomes slower but less flickering.
5. Try changing the value of WorldInfo.optimalThreadCount. This field specifies how many threads are used to simulate the physics of the world. Depending on the world you can get a better performance by reducing or increasing this value. In general it is better to have a low number of threads for simple worlds and a bigger number of threads for complex worlds that include several robots physically independent from each other.
6. Disable unnecessary shadows. Webots uses a lot of CPU/GPU power to compute how and where the objects shadows are cast. But shadows are irrelevant for most simulation unless they should explicitly be seen by Cameras. Unnecessary shadows can be disabled by unchecking the castShadows field of light nodes: PointLight, SpotLight, or DirectionalLight.
7. Simplify your simulation by removing unnecessary objects. In particular, try to minimize the number of Physics nodes. Avoid using a Solid nodes when a Transform or a Shape would do the trick.
8. Simplify the bounding objects to increase the speed of the collision detection. Replace complex primitives, like Cylinder, IndexedFaceSet, Mesh and ElevationGrid by simpler primitives, like Sphere, Capsule, Box and Plane. Avoid using a composition of primitives (in a Group or a Transform) when a single primitive would do the trick.
9. Set an empty string in the controller field for any Robot nodes that don't need to be controlled, instead of using the void controller.