Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Radius
MDATA_CLOUD_CREATE_BRUSH_RADParameter: Density
MDATA_CLOUD_CREATE_DENSITYParameter: Maximum Size
MDATA_CLOUD_CREATE_MAX_SIZEParameter: Threshold
MDATA_CLOUD_DRAW_THRESHOLDParameter: Clear
MDATA_CLOUD_CLEARParameter: Fill Plane
MDATA_CLOUD_FILL_PLANEParameter: Fill Sphere
MDATA_CLOUD_FILL_SPHEREParameter: Distance
MDATA_CLOUD_SMOOTH_B_DISTParameter: Variance
MDATA_CLOUD_SMOOTH_B_VARParameter: Shape
MDATA_CLOUD_SMOOTH_B_SPLINEParameter: Smooth Borders
MDATA_CLOUD_SMOOTH_BORDERSParameter: Strength
MDATA_CLOUD_SMOOTH_A_STRParameter: Variance
MDATA_CLOUD_SMOOTH_A_VARIANCEParameter: Smooth All
MDATA_CLOUD_SMOOTH_ALLParameter: Remap
MDATA_CLOUD_REMAP_SPLINEParameter: Remap
MDATA_CLOUD_REMAPParameter: Quality
MDATA_CLOUD_DISPLAY_QUALITYParameter: Render Preview
MDATA_RENDERPREVIEW_BTN