"LanuHum" <Lan### [at] yandexru> wrote:
> Hello! I created a picture with a gradient. I want to use it as a height map for
> a sphere. However, only gray stripes are visible on the sphere.

That's because you're only perturbing the normal vectors on the smooth sphere to
make the light reflect in different directions than it normally would, and so
produce the illusion that there is a "texture" on the surface when there isn't.

There are articles on the web and maybe a POV-Ray FAQ that show the shadows cast
by objects that are really shaped that way vs a smooth object with a normal map.

What you want to do is "surface displacement" where you actually change the
geometry of the surface of your sphere.

Luckily, myself, WFP, and Maetes have worked on this.

Your best bet is to use whatever function makes your stripes to modulate the
radius of your sphere so that those points have the actual height dictated by
the function.

https://news.povray.org/povray.binaries.images/thread/%3C5f16dc29%40news.povray.org%3E/

https://news.povray.org/povray.advanced-users/thread/%3Cweb.67b47b18cb1bd5e34d0a98d30225ff5%40news.povray.org%3E/

You can also look at Mike Williams' isosurface tutorial where he has several
examples of using functions to change the surface of a sphere.

Hope that helps.

- BE

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