This is a generator object which takes each particle (or field vector) and constructs renderable geometry from it.
In the case of the field vectors, most particle shapes and the collider bounds, the generated object is a spline and you can render it using the X-Particles material.
In a few cases, the object is a polygon object and you should use the X-Particles Object Shader in a channel material.
xpDisplayRender Object tab settings.
Set to Particle Display, by default, this drop-down menu selects which type of object will be rendered.
The alternative options are: Flowfield Display, Modifier Field, Collider Bounds, ExplosiaFX Velocity and FLIP Velocity.
The particle shapes are rendered.
You will need to supply an emitter in the Emitter link field.
Most shapes are rendered as splines but some are polygon objects.