Particle system fog problem

I am making a Fog particle system, and I have 2 issues.

  1. How do I make my particles to disappear near the camera so it will blend out at close range?

  2. When I run forward and turn back, it appears that particles stuck behind which leads to lag. How do I set max allowed distance between particles or make them draw properly in area around while moving?

  1. You need to customize your own shader for this, but Unity 2017.3 (still beta) provides Standard Particle Shader which include fading on camera distance.

  2. High amount of overdraw and large camera coverage by translucent objects are known to create performance issues. You should simply reduce emission rate and lower max particle size in renderer module. If you can write c# script, get/set particles to check the distance between each particle from your camera, if it is within the range, do a Mathf.Lerp to quickly reduce the remaining lifetime of that particle.