What does sorting fudge in ParticleSystems actually do? I have several questions that could be answered if I have a better understanding: What are the units? Sometimes I need to set high values such as -2000, or 2000 to have an effect. I had assumed that Sorting Fudge is in world-space units which are added to the distance from the camera before an object is sorted with other objects, but the units in the thousands didn't make sense in my scale. How are particle objects sorted between each other, without considering sorting fudge? I assume that either the centroid or the closest corner of the bounding box is sorted, and that order becomes the draw order. Is there a way for me to explicitely set a reference point for geometry for the purpose of computing a sort order (i.e. can I set the bounding box via code)? Because the bounding box is changing every frame, I'm finding that the sort order between different particles changes frequently causing visual popping. I could prevent the popping by setting the world-space sort point to something that doesn't vary each frame. How does Sort Fudge effect drawing with other transparent objects in the scene? Can MeshRenderers have a sort layer? I'm facing two different challenges, and I'm hoping that I can use Sorting Fudge to solve them, but I haven't had success yet. 1) I have a smoke trail that is built by a custom component that creates a Mesh and MeshRenderer. This trail is overlapped by smoke particles that serve to break up the edge. The particles and smoke trail sometimes pop in the order that they sort. I would like the smoke particles to almost always draw behind the smoke. I prefer not to use explicit renderQueues because I have other effects that can overlap, such as an explosion. I don't want to force the smoke particles to draw always behind the explosion if the explosion is actually the most distant object. 2) Within an explosion effect, I have separate non-batching particles for sparks, fire, and a glow sprite. If I have two explosions that sit roughly at the same distance from the camera, I would like Unity to sort in a batch-friendly manner (e.g. this order: fire1, fire2, spark1, spark2, glow1, glow2). Only if the depths vary dramatically, such as by more than the sort fudge, would the two explosions' particles stagger (e.g. fire1, spark1, glow1, fire2, spark2, glow2). I appreciate any details about how sorting works, and how sorting fudge effects sorting.