"gulino" <nomail@nomail> wrote:

> Then there is no reason to use patches. Can you help me how to do it with
> heightfield?

https://wiki.povray.org/content/Reference:Height_Field

You can use either an image file or a pigment pattern to control the elevation,
or you can use a function if you have an equation that would give you the kind
of surface that you want.

f_hetero_mf(x,y,z, P0, P1, P2, P3, P4, P5): f_hetero_mf (x,0,z) makes
multifractal height fields and patterns of 1/f noise. Multifractal refers to
their characteristic of having a fractal dimension which varies with altitude.
Built from summing noise of a number of frequencies, the hetero_mf parameters
determine how many, and which frequencies are to be summed. An advantage to
using these instead of a height_field {} from an image (a number of height field
programs output multifractal types of images) is that the hetero_mf function
domain extends arbitrarily far in the x and z directions so huge landscapes can
be made without losing resolution or having to tile a height field. Other
functions of interest are f_ridged_mf and f_ridge.

P0 : H is the negative of the exponent of the basic noise frequencies used in
building these functions (each frequency f's amplitude is weighted by the factor
f - H ). In landscapes, and many natural forms, the amplitude of high frequency
contributions are usually less than the lower frequencies. When H is 1, the
fractalization is relatively smooth (1/f noise). As H nears 0, the high
frequencies contribute equally with low frequencies as in white noise.
P1 : Lacunarity is the multiplier used to get from one octave to the next. This
parameter affects the size of the frequency gaps in the pattern. Make this
greater than 1.0
P2 : Octaves is the number of different frequencies added to the fractal. Each
Octave frequency is the previous one multiplied by Lacunarity, so that using a
large number of octaves can get into very high frequencies very quickly.
P3 : Offset is the base altitude (sea level) used for the heterogeneous scaling
P4 : T scales the heterogeneity of the fractal. T=0 gives straight 1/f (no
heterogeneous scaling). T=1 suppresses higher frequencies at lower altitudes
P5 : Generator type used to generate the noise3d. 0, 1, 2 and 3 are legal
values.

https://wiki.povray.org/content/Reference:Functions.inc

https://news.povray.org/povray.general/thread/%3Cweb.63ea928499ce13121f9dae3025979125%40news.povray.org%3E/?ttop=444970
&toff=150&mtop=439826

See what you can to work with that, and then come back with any questions.
Also there are the files in the example directories supplied with your POV-Ray
distribution, and also the drop-down Insert Menu in the editor.
Probably under Special Shapes > Isosurfaces and Height_Fields, ....

- BW

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