ParticleSystem reduce Object Count I'm using Hair Particles to spawn grass on hills. Unfortunately I cannot convert more than 10 000 grass particles to mesh because every single particle gets converted into a separate object. Any  more than 10-20k and blender will crash or take extremely long. Is there way to Convert all the Particles into a single Object or just somehow reduce the Object count? The Poly count is not high at all.
The solution is to use Particle Instance Modifier to instantiate the grass object, instead of Dupli Object option found in the particle system settings.
https://docs.blender.org/manual/en/latest/modeling/modifiers/simulate/particle_instance.html



Benefits of using the modifier to instantiate an object:


much better viewport performance (especially in 2.79)
no need of pre-rotating the models to use random Z rotation (useful for vegetation)
fast conversion to a single mesh by AltC -> Mesh


How to:


Select your (single) grass model and hit AltG to move it to 0,0,0
Add Particle Instance Modifier to this grass model
In the modifier's options, pick the ground object and it's particle system
The grass should now be instantiated similarly like using Dupli Object (if not, check if your particles are alive, or just tick all of these checkboxes under Show Particles When)
To convert the instantiated grass to single mesh, make sure you have the grass selected and press AltC -> Mesh


There are also some disadvantages though, like using vertex groups for particle size (length) doesn't seem to work (maybe there are some more, but nothing important for me - you will have to find out).