Thanks Rosemaryr, I very much appreciate all the effort to answer my questions…
Now, while on the subject of fabrics, I know this is a little off topic but might be helpful to someone out there who is doing fabric shaders. I’m in no way an expert on them, but there are some basics that might not be real obvious, but might be helpful to consider.
Often you see clothing fabric in 3D renders that looks very thick and heavy, when it’s supposed to be light and soft and comfortable. Part of the reason for that is the shaders.
Face it, fabric shaders are difficult to do well. And part of the reason is this:
Many times I’ve said that there are three things that light can do when it encounters a material:
1. Bounce off
2. Bounce around inside, then come out
3. Pass thru
What makes fabrics so challenging, and often complicated, is that with many fabrics (of course, not all), light does all three things.
To see this, myy biggest recommendation is to try something simple to get a feel for how fabrics respond to light: take a sample of a fabric outside, like a typical, comfortable knit t-shirt or shorts, and hold it up to the sunlight. What do you see?
Well, you probably see a speckled light pattern of sunlight coming thru. And you probably see the fabric even glowing a bit. Why? Well, think about how the fabric is at the thread level. It was made by weaving threads in a consistent, criss cross pattern. And the threads themselves are generally made of much smaller threads wrapped together. Clothing fabrics are generally designed to be comfortable, which means light and airy and soft, which means that they’re generally not going to be very opaque and thick and heavy. Of course, there are exceptions. But the vast majority are designed to have air pass thru, which means lots of light passes thru. You probably don’t want to wear a fabric that isn’t woven, and doesn’t let air/light pass thru (like a rubber, or example).
So it becomes very clear that light is doing all three things I mentioned.
It must be bouncing off and into our eyes, or we wouldn’t see it. That’s easy. But it’s also passing thru, but in a speckled pattern, consistent with the weave. And it’s also bouncing around inside the fabrics, then coming out and into your eyes because of the properties of the thread. That’s what gives it a slight glow.
What does that all mean? Well, it becomes pretty clear that you’re going to need many of the material properties applied to your fabric. You’ll need color, bump, and highlight, but you’ll also need some alpha since you saw how light passes thru, and you might need some translucency. And the alpha isn’t uniform, it’s in a weave pattern since the light passes thru the spaces between the threads. But due to the translucency of the threads there’s also light passing thru them. But light also bounces around inside the fabric, then comes out and into your eyes. It’s often a subtle effect, but just as often it’s the subtlety that really makes viewers believe it. And what describes light bouncing around inside and coming out and into our eyes? SSS, of course. Or maybe even a Glow.
So my only point is that texturing fabrics is a challenge, and is not as simple as you might think. It requires some thought, and I’d suggest that if you want to make really nice textures you study the fabric first before you attempt to build a shader.