Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See page_maxonapi_getting_started_foundations_cinema_parameters.
Parameter: Birthrate Viewport
PARTICLEOBJECT_BIRTHEDITOR
Parameter: Birthrate Renderer
PARTICLEOBJECT_BIRTHRAYTRACER
Parameter: Visibility
PARTICLEOBJECT_VISIBILITY
Parameter: Start Emission
PARTICLEOBJECT_START
Parameter: Stop Emission
PARTICLEOBJECT_STOP
Parameter: Seed
PARTICLEOBJECT_SEED
Parameter: Relative Speed
PARTICLEOBJECT_RELATIVE_SPEED
Parameter: Lifetime
PARTICLEOBJECT_LIFETIME
Parameter: Lifetime Variation
PARTICLEOBJECT_LIFETIMEVAR
Parameter: Speed
PARTICLEOBJECT_SPEED
Parameter: Speed Variation
PARTICLEOBJECT_SPEEDVAR
Parameter: Rotation
PARTICLEOBJECT_ROTATION
Parameter: Rotational Variation
PARTICLEOBJECT_ROTATIONVAR
Parameter: End Scale
PARTICLEOBJECT_SIZE
Parameter: Scale Variation
PARTICLEOBJECT_SIZEVAR
Parameter: Tangential
PARTICLEOBJECT_TANGENTIAL
Parameter: Show Objects
PARTICLEOBJECT_SHOWOBJECTS
Parameter: Render Instance
PARTICLEOBJECT_RENDERINSTANCES
Parameter: Emitter Type
PARTICLEOBJECT_TYPE
Parameter: X-Size
PARTICLEOBJECT_SIZEX
Parameter: Y-Size
PARTICLEOBJECT_SIZEY
Parameter: Angle Horizontal
PARTICLEOBJECT_ANGLEH
Parameter: Angle Vertical
PARTICLEOBJECT_ANGLEV
Parameter: Mode
PARTICLEOBJECT_MODE
Parameter: Modifiers
PARTICLEOBJECT_INCLUDE