I performed a quick and dirty test by just calling Clear on the current particle system before emitting and that made emitting much faster, but that's perhaps not a fair comparison. Is this due to the particle system needing to find gaps in its internal arrays to put the new particles? Would it be more efficient to use many separate smaller particle systems, 1 for each burst of particles, and then reuse the systems for future bursts only once all its current particles have expired? My thinking is this would make finding room to place the newly emitted particles much quicker. The Add system almost always performs significantly better than the Remove system when it comes to emitting new particles.

When particles are emitted to the Add system they are all emitted with a constant lifetime, whereas the Remove voxels system has a randomized lifetime per particle. Each system has a max capacity of 20,000 particles and has particles emitted in variable sized bursts, with multiple bursts overlapping each other in time, meaning that the particles in the system have a range of different remaining lifetimes. Right now I use 2 particle systems for the effect shown above, 1 for adding voxels and 1 for removing them. I was wondering why this might be and have a few ideas. Sometimes I can emit several thousand particles in a few milliseconds, and other times a couple hundred particles or less will take over 20 milliseconds (in both cases there's still plenty of room in the system for the new particles). I was digging into my performance bottleneck with emitting particles some more and noted some surprising results.

Magicavoxel lines upwards