Repel
The "Repel" feature will procedurally remove and/or adjust instances scales/rotations near a defined distance threshold from the objects linked to the chosen collection.
By default, the proximity contact will be the faces of the objects meshe. If your assets are too high poly it might be a good idea to change the proximity contact option.
Consider Volume Option
Assuming your repel object possesses a volume, you can use the 'Consider Volume' option if you'd like to also cull instances located inside or outside the volume.
Reminder:
If you only care about the volume feature, we have a more simplistic culling mask available.
Pro Tip:
To generate a clean grass scatter near pavements, assuming you have a clump model to cover the large areas and a tiny grass model to fill the gaps, here's the most memory-efficient technique you can use:
On the large clump system, enable the Proximity → Repel feature and choose your pavement collision collection
Do the same for the tiny system but reverse the influence and use the 'consider volume' option to also cull points located within the object volume.
Lean Near Objects
The Repel feature is also able to procedurally orient the instances near a given distance threshold from the chosen objects inside the linked collection.
By default, the proximity contact will be the faces of your objects meshes. If your assets are too high poly it might be a good idea to change the contact option.
Use Case:
Useful if you'd like to fake interaction with objects without doing destructive time-consuming soft-bodies simulation.
If a more precise simulation is needed, you will need to export your scatter-systems as a mesh in order to use the the simulation method of your choice (soft-bodies simulations are out of the scope of a scattering tool relying on the technology of instancing).
Beginner Misconception:
Achieving physically accurate collisions between, let say, your individual hundreds of thousands blades of grass with your crowd animation, is not a realistic expectation of what scattering is supposed to do, it breaks the principle of instancing! What is needed in this case is a soft-body simulation with the exported instances, merged as one single object!
Note:
Note that proximity features were originally called "Cull Near" and "Lean Near" in older versions. Since Scatter5.3 we merged both functionalities into two all-in-one "repel" slots
Outskirt Effects
Note:
This feature is heavy to compute.
This feature works best with a contrasted distribution.
If you'd like to create clumps transition effects with this feature, please consider the dedicated clump distribution method with influences on scale and orientation available.
The "Outskirt" feature will procedurally find the delimitation of your scatter from the given threshold value in order to create a transition effect.
Use Case:
Useful for many scenarios, such as creating rugs, or imitating nature behaviors! Plants/trees located on the outskirt of a densely populated area will always have a lower size and are slightly tilted in the outward direction of thepack.
