Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Texture
HATCHINGSHADER_TEXTUREParameter: Tile UV
HATCHINGSHADER_TILEParameter: Rotational UV
HATCHINGSHADER_ROTATIONALParameter: Scale
HATCHINGSHADER_SCALEParameter: Rotate UV
HATCHINGSHADER_ROTATEParameter: Offset U
HATCHINGSHADER_OFFSET_UParameter: Offset V
HATCHINGSHADER_OFFSET_VParameter: Density
HATCHINGSHADER_DENSITYParameter: Density U
HATCHINGSHADER_DENSITY_UParameter: Density V
HATCHINGSHADER_DENSITY_VParameter: Scatter U
HATCHINGSHADER_SCATTER_UParameter: Scatter V
HATCHINGSHADER_SCATTER_VParameter: Spacing U
HATCHINGSHADER_SPACE_UParameter: Variation
HATCHINGSHADER_SPACE_U_VARParameter: Spacing V
HATCHINGSHADER_SPACE_VParameter: Variation
HATCHINGSHADER_SPACE_V_VARParameter: Scale U
HATCHINGSHADER_SCALE_UParameter: Variation
HATCHINGSHADER_SCALE_U_VARParameter: Scale V
HATCHINGSHADER_SCALE_VParameter: Variation
HATCHINGSHADER_SCALE_V_VARParameter: Rotate
HATCHINGSHADER_STOKE_ROTATEParameter: Crosses
HATCHINGSHADER_CROSSEDParameter: Cross Rotation
HATCHINGSHADER_CROSS_ROTATEParameter: Dark Stroke Color
HATCHINGSHADER_STROKE_COLORParameter: Light Stroke Color
HATCHINGSHADER_STROKELIGHT_COLORParameter: Background Color
HATCHINGSHADER_BACK_COLORParameter: Show Dark Strokes
HATCHINGSHADER_DARK_STROKESParameter: Show Light Strokes
HATCHINGSHADER_LIGHT_STROKESParameter: Shade Levels
HATCHINGSHADER_LEVELSParameter: Threshold
HATCHINGSHADER_THRESHOLDParameter: Shadows
HATCHINGSHADER_SHADOWParameter: Diffuse
HATCHINGSHADER_DIFFUSEParameter: Specular
HATCHINGSHADER_SPECParameter: Illumination
HATCHINGSHADER_ILLUMParameter: Use Bump
HATCHINGSHADER_BUMPParameter: Camera
HATCHINGSHADER_CAMERAParameter: Lights
HATCHINGSHADER_LIGHTSParameter: Specular
HATCHINGSHADER_SPECULARParameter: Illumination
HATCHINGSHADER_ILLUMINATIONParameter: Shadow
HATCHINGSHADER_SHADOWSParameter: Modifies Contrast
HATCHINGSHADER_CONTRASTParameter: Use Lights
HATCHINGSHADER_INCEXCParameter: Lights
HATCHINGSHADER_INCEXC_LIGHTS