The TurboSmooth modifier with the Render Iters function is on the curtain model: from 1 to 2 values, if necessary, you can add the necessary number of segmentation by changing this indicator to a large number.
OBJ (OBJ, filesize: 5.44 MB), 3DS (3D Studio, filesize: 7.75 MB), MAX (Autodesk 3ds Max, filesize: 7.75 MB), FBX (Autodesk FBX, filesize: 11.4 MB)