Force attenuation and containers
Both force attenuation and containers impact Geometry forces.
Force attenuation
Attenuation applies to Geometry forces just as it does to any other force type. For Geometry forces, the distance used is the distance away from the closest point on the geometry’s surface instead of the distance away from the force’s position.
Both Force:Strength and Force:Align strength can be attenuated, each with their own settings. In the example we’ve been using, the “Rook” Geometry force does not have its main strength attenuated but does have its align strength attenuated. This technique is used here so that the leaves are free to orient in any fashion until they get very close to the surface of the geometry.
In the screenshot above, the “Rook” Geometry force is selected and the orange lines indicate the attenuation distance for alignment attenuation. There is no main force strength attenuation on this force, but, if there were, it would be indicated by similar white lines.
Containers
Similar to attenuation, forces can also have an area of effect controlled by another "container" Geometry force, limiting its area of effect. You can indicate an area to be included or excluded for a particular force by setting the corresponding properties in the Container force property group to the name(s) of the geometry forces you wish to use as containers.
In the following image, there are four forces: two Direction forces and two Geometry forces with a sphere mesh indicating the area of effect for the corresponding direction force. The branch is affected by the Direction forces in a very precise manner.