Tom's POVRay Fabric Texture Example

The picture above was made with this POV file. The texture was formed in part by the bump map shown below.

The bump map was made with this POV file.

About this Texture

This is an example of how to render a realistic looking fabric, at fairly high detail.

The shading comes from the bump map pictured above. In adition, looking at the fabric you will see apparent vertical and horizontal streaks. One bozo pattern was stretched out horizontally, and another vertically. These two patterns were then used as pigments in the checker pattern, such that the horizontal streaks appear on horizontal bumps, and the vertical streaks appear on the vertical bumps. Even under close examination, this creates a strung impression of horizontal and vertical threads woven together.

Specs

Bump maps are applied to a unit square. Note that within one square, we cover a two-by-two threads area. In my example I scaled this down to 0.17 (arbitrarily picked), which ammounts to 1/0.17 = 5.88 bump maps per unit, or 11.76 threads per unit.

The checker pattern puts one checker square on each unit square. To match this to the bump map, it has to be scaled in half, so that we have two-by-two checker squares in each unit square, just like the bump map. Additionally it will need to be scaled by whatever amount the bump map has been scaled by (0.17 in my example).

Problems and Future Work

When you get far enough away from this pattern, you can develop some pretty severe aliasing. For rendering at a distance, anti-aliasing must be used, but be careful because there is so much detail that an adaptive anti-alias can spend a lot more time than needed on this fabric.

As you can see, it looks a bit odd from oblique angles. This is a problem with any bump map. If you really need that much detail in your fabric, you should probably model the individual threads.

Copyright

This web page, the associated image(s), and POV files are all copyright 2004 by Thomas A. Fine (that's me!). I hereby grant free distribution rights, including for-profit uses, in full or in part, provided only that copyright notices are preserved and due credit is given.

WARNING: This POV object is based on a real object. I'm not aware of any legal issues related to the design of that real object. It is the user's responsibility to cover your ass.

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