This specific 3D model, "Curtain Low-poly 3D model 66", is an asset made available by "Unknown author".
You can download this asset for free at "Unknown platform" by following the link.
This specific 3D model is provided under the "Unknown license" framework.
OBJ (OBJ, filesize: 1.6 MB), BLEND (Blender, filesize: 1.21 MB), FBX (Autodesk FBX, filesize: 1.67 MB), GLTF (glTF, filesize: 1.39 MB)