import os
obj_dir = hou.ui.selectFile(title="Select Obj Directory", file_type=hou.fileType.Directory)
obj_dir_expanded = hou.expandString(obj_dir)
obj_files = os.listdir(obj_dir_expanded)
file_nodes = []
loader = hou.node("/obj").createNode("geo", "OBJ_Loader")
for obj in obj_files:
obj_file_node = loader.createNode("file", obj)
obj_file_node.parm("file").set(obj_dir + obj)
obj_file_node.parm("missingframe").set(1)
file_nodes.append(obj_file_node)
merge_objs = loader.createNode("merge", "OBJ_Merger")
for node in file_nodes:
merge_objs.setNextInput(node)
loader.layoutChildren()
merge_objs.setDisplayFlag(True)
merge_objs.setRenderFlag(True)