Here is another example:

suppose you have a heightfield. Now close to it, you take a piece of 
plane and you play with normal (you look from above). After lot of work,
your piece of plane look exactly like the heightfield (of course if you 
look from the side, you see the elevation of the heightfield but 
the plane is, of course, still flat!). You cannot say which is the 
heightfield. You calculate one image, say height.tga. Now if you scale 
both the heightfield and the piece of plane by the same factor x, and 
if you modify the camera in a proper way, the piece of plane will still
look exactly like the heightfield. Moreover, if you calculate the image,
say 
height2.tga, you get the same image than height.tga (perhaps if one
choose
a good heightfield (simple), it is possible to get with normal the same 
thing. Atfer this one make the test with scaling.
This could be a interesting test for MegaPov)

Fabian.

Ken wrote:
> 
> Nieminen Juha wrote:
> 
> >   A normal pattern actually simulates a heightfield.
> 
> Am I missing something here ?
> 
> As far as I know a normal has no releationship to a height field in any
> way what so ever. The models are entirely different.
> 
> When you apply a normal to a surface it's properties are controlled
> explicitly by two parameters. The first is the float value after the
> pattern type i.e. normal { bumps 1 } which sets the normal depth. The
> second is the scale of the pattern which only effects the scale of the
> pattern itself and not the depth of the normal pertubation. Scaling the
> normal will not affect the depth of the normal pertubation and was never
> intended to. It may effect the depth of the pattern but it will not
> change the depth or height of the pertubation itself. If you want this
> value to change then you must change the float value after the pattern
> type and not rely on the scale value to do this for you. Any other model
> for the normal would not be correct.
> 
> --
> Wishing you Seasons Greetings, A Merry Christmas, and A Happy New Year !
> Ken Tyler -  1200+ Povray, Graphics, 3D Rendering, and Raytracing Links:
> http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

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