These parameters can only be seen with an emitter attached to the mesh node: they can be adjusted individually for each emitter, making it possible to define specific settings and values for the emitters to generate a much better and diversified mesh. To get your hands on these parameters, select an emitter that is grouped under the appropriate mesh node.
Radius
The mesh engine draws a sphere around every particle, blends them with the → “Smooth” parameter, and extracts a surface. The radius of these spheres is defined here. A good starting value is: Radius = Polygon size * 1.7
Subtractive field
Normally meshes from multiple emitters are added, but you can also subtract meshes.