C4D merge Mat

#C4D Merge mat
#Coded by graphos more information
#graphos.xyz
#https://vimeo.com/207692957
import c4d

def main():
        mats = doc.GetActiveMaterials()
        list_tags = list()

        for mat in mats:
            obj_link = mat[c4d.ID_MATERIALASSIGNMENTS]

            for i in xrange(obj_link.GetObjectCount()):
                list_tags.append(obj_link.ObjectFromIndex(doc, i))

        doc.StartUndo()
        for tag in list_tags:
            doc.AddUndo(c4d.UNDOTYPE_CHANGE, tag)
            tag[c4d.TEXTURETAG_MATERIAL] = mats[0]

        for mat in mats[1:]:
            doc.AddUndo(c4d.UNDOTYPE_DELETE, mat)
            mat.Remove()

        doc.EndUndo()

        c4d.EventAdd()

if __name__=='__main__':
    main()