io_gltf/description/fgltfexporter.hParameters are accessed with cinema::C4DAtom::GetParameter() and cinema::C4DAtom::SetParameter(). See Parameters.
Parameter: File Format
GLTFEXPORTER_FILEFORMATGLTFEXPORTER_FILEFORMAT_GLTFGLTFEXPORTER_FILEFORMAT_GLBParameter: Current Frame
GLTFEXPORTER_CURRENTFRAMEParameter: Custom Frame
GLTFEXPORTER_CUSTOMFRAMEParameter: Transform
GLTFEXPORTER_PSRANIMATIONSParameter: Morph
GLTFEXPORTER_MORPHANIMATIONSParameter: Skin
GLTFEXPORTER_SKINANIMATIONSParameter: Bake Animation
GLTFEXPORTER_BAKEANIMATIONSParameter: Textures
GLTFEXPORTER_TEXTURESParameter: Width
GLTFEXPORTER_TEXTURES_WIDTHParameter: Height
GLTFEXPORTER_TEXTURES_HEIGHTParameter: Resize Textures
GLTFEXPORTER_TEXTURES_RESIZEGLTFEXPORTER_TEXTURES_RESIZE_OFFGLTFEXPORTER_TEXTURES_RESIZE_DONTENLARGEGLTFEXPORTER_TEXTURES_RESIZE_ALWAYSParameter: Double Sided
GLTFEXPORTER_DOUBLESIDEDParameter: Cameras
GLTFEXPORTER_CAMERASParameter: Instances
GLTFEXPORTER_INSTANCESParameter: Normals
GLTFEXPORTER_NORMALSParameter: UVs
GLTFEXPORTER_UVSParameter: Flip Z
GLTFEXPORTER_FLIPZ