Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Birthrate Viewport
PARTICLEOBJECT_BIRTHEDITORParameter: Birthrate Renderer
PARTICLEOBJECT_BIRTHRAYTRACERParameter: Visibility
PARTICLEOBJECT_VISIBILITYParameter: Start Emission
PARTICLEOBJECT_STARTParameter: Stop Emission
PARTICLEOBJECT_STOPParameter: Seed
PARTICLEOBJECT_SEEDParameter: Relative Speed
PARTICLEOBJECT_RELATIVE_SPEEDParameter: Lifetime
PARTICLEOBJECT_LIFETIMEParameter: Lifetime Variation
PARTICLEOBJECT_LIFETIMEVARParameter: Speed
PARTICLEOBJECT_SPEEDParameter: Speed Variation
PARTICLEOBJECT_SPEEDVARParameter: Rotation
PARTICLEOBJECT_ROTATIONParameter: Rotational Variation
PARTICLEOBJECT_ROTATIONVARParameter: End Scale
PARTICLEOBJECT_SIZEParameter: Scale Variation
PARTICLEOBJECT_SIZEVARParameter: Tangential
PARTICLEOBJECT_TANGENTIALParameter: Show Objects
PARTICLEOBJECT_SHOWOBJECTSParameter: Render Instance
PARTICLEOBJECT_RENDERINSTANCESParameter: Emitter Type
PARTICLEOBJECT_TYPEParameter: X-Size
PARTICLEOBJECT_SIZEXParameter: Y-Size
PARTICLEOBJECT_SIZEYParameter: Angle Horizontal
PARTICLEOBJECT_ANGLEHParameter: Angle Vertical
PARTICLEOBJECT_ANGLEVParameter: Mode
PARTICLEOBJECT_MODEParameter: Modifiers
PARTICLEOBJECT_INCLUDE