Advanced Curtain Shader - Blender Cycles

Physically-correct tool for realistic curtains and cloth fabric for Blender 2.80 and up

Creating a good curtain material is hard and time consuming: sometimes we want it to let some light through and glow when hit by sunlight, some others we want it just to be translucent and blind direct light. And transparency does seem always off: it' s either too much or it does resemble frosted glass instead of thin fabric. Also, common tricks to let light through do destroy reflections on glossy surfaces

That's because, in reality, fabric involves a lot of interactions with light: threads interwoven do absorb and scatter some rays, while slightly deforming and letting through others. The physics behind light interactions require to carefully craft a system of interconnected curves, fine-tuning each parameter