Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Texture
SLA_PROJECTOR_TEXTURE
Parameter: Projection
SLA_PROJECTOR_PROJECTION
Parameter: Offset X
SLA_PROJECTOR_OFFSET_X
Parameter: Offset Y
SLA_PROJECTOR_OFFSET_Y
Parameter: Length X
SLA_PROJECTOR_LENGTH_X
Parameter: Length Y
SLA_PROJECTOR_LENGTH_Y
Parameter: Tiles X
SLA_PROJECTOR_TILES_X
Parameter: Tiles Y
SLA_PROJECTOR_TILES_Y
Parameter: Tile
SLA_PROJECTOR_TILE
Parameter: Seamless
SLA_PROJECTOR_SEAMLESS
Parameter: Position
SLA_PROJECTOR_POSITION
Parameter: Size
SLA_PROJECTOR_SIZE
Parameter: Rotation
SLA_PROJECTOR_ROTATION
Parameter: Paste Tag
SLA_PROJECTOR_PASTE_TAG