Modifiers have a set of fixed attributes which all modifiers share. These are known as static modifier attributes and can be seen at the top of a modifier rollout.

All attributes can be animated or expression driven to create more interesting flocking simulations.

The majority of these attributes control the type and size of the modifier’s volume shape. You can read about these attributes in the Modifier Volume section.

Weight

The weight of a modifier is a scale factor which determines how much influence it should have. The value ranges from 0 to 1, with 1 meaning that the modifier has full influence and 0 meaning it has none.

The weight can be used in a number of situations such as to enable/disable a specific modifier, or to blend between different modifiers when multiple modifiers are affecting the same set of particles.

Modifier Method

The Modifier Method attribute determines how a modifier should apply its dynamic modifier attributes to particles within its volume. There are 2 modes of operation; Override and Additive.

Override

This is the default modifier mode and simply means that any particles within the volume of this modifier will have their simulation attributes overridden by the value given by this modifier.

The override value is also interpolated between the modifier value and the system value based on the volume influence, so if the influence is 50%, the actual value used will be a 50% blend between the modifier value and the system value.

The actual logic is as follows:

               From:            To:               Alpha:
linear_interp (current_value,   modifier_value,   volume_influence);

See Modifier Volume to learn more about the volume influence.

Additive

This modification method means that the value specified by each dynamic modifier attribute will be added to the current system value for any particles within the modifier’s volume. It is also possible to use negative values in this mode, which will subtract from the system value.

The added value is also interpolated between the modifier value and 0 based on the volume influence. So if the influence is 50% the actual value added will be 50% of the modifier value.

The actual logic is as follows:

               From:       To:               Alpha:
linear_interp (0.0,        modifier_value,   volume_influence)  +  current_value;

See Modifier Volume to learn more about the volume influence.