The 'Sim' tab includes switches for turning various simulation calculations components on and off.

Gravity: Enables Gravity force for the selected objects. There are 4 options available: Inactive - The object is not considered in gravity computations. Both - The object creates a gravity field and is pulled by gravity forces. Cause - The object generates a gravity field. It does not react to gravity forces. Affected - The object does not create gravity, but is pulled by gravity forces.

Magnetism: Enables Electro Magnetic simulation. Magnetism is different from gravity in that it is a signed quantity: similar charges repel each other, opposite charges attract each other. The four magnetism alternatives - Inactive, Both, Cause, Affected - work the same way as in the Gravity setting above.

Fluid Dynamics: Enables fluid simulation. See 'Gravity' above for the option types. Typically only fluid specialized objects such as a fan have the 'Cause' option set i.e. they generate a fluid environment. Other simulated objects use 'Fluid Dynamics = Affected' option.

Collision Properties

Collision Detection: Enables Collision detection as follows:

Collision Accuracy: Defines how accurately the collision point is examined. The higher the value, the sooner collision (= object volume penetrating another object volume) is detected. High values naturally increase computation time. If the object shape is complex (includes sharp extrusions etc.), a high collision accuracy may be necessary to prevent object volume overlapping.