https://player.vimeo.com/video/750287352?h=ed43604a62&badge=0&autopause=0&player_id=0&app_id=58479
Set to Absolute by default.
The alternative setting is Particle Radius.
The distance is a set value.
Note: If the radii of the particles varies, you may see some areas where the particles overlap and other areas with larger gaps than expected between them.
nexus_nxpush_010[Absolute].mp4
In this animation, Distance Mode is set to Absolute, pushing particles 10cm away from each other.