[NOTE] In the scene only curtain, no walls and window.
One of the six options for this curtain, which you will find in my models. In the archive only the curtain, the beam mechanism, cargo and lace. Everything is one object with multimaterial.
Each element has a scan, a grid of quads, bounding edges are everywhere, the model is optimized for smoothing, there is a Turbosmooth modifier in the stack of the model with a double iteration level in the rendering.
The width of the curtain is 700 mm. The top is 17658, the polygon is 17408. The curtain itself, which can be rendered without a mechanism, is about 12,000.
On the model 4 of the material. The main fabric material has a simple adjustment. To change the color, you just need to change it in the VrayColor. The basic shape of the folds is set by the geometry of the model, and the fine folds and details are specified by the normal map, which I shot from the high poly model, the intensity of these folds and details can be changed in the NormalMap map settings, now the value 2 is everywhere, but it can be reduced. Did on the reference, which is very messed up.