Sphere-shaped 3D particle collision shape affecting [GPUParticles3D] nodes. Sphere-shaped 3D particle collision shape affecting [GPUParticles3D] nodes. [b]Note:[/b] [member ParticlesMaterial.collision_mode] must be [constant ParticlesMaterial.COLLISION_RIGID] or [constant ParticlesMaterial.COLLISION_HIDE_ON_CONTACT] on the [GPUParticles3D]'s process material for collision to work. [b]Note:[/b] Particle collision only affects [GPUParticles3D], not [CPUParticles3D]. The collision sphere's radius in 3D units.