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27 Nov 2024 17:30:01 EST (-0500)
  height_fields (Message 1 to 4 of 4)  
From: klotera
Subject: height_fields
Date: 4 Sep 2002 20:05:10
Message: <web.3d769f5626cc84be295e176c0@news.povray.org>
I have a question about height_fields.. i just learned them the other night
and I have been trying to do different texture options with them (the
actual height-field object, not the reference image) and i've foud I cant
do alot of things, like apply apply a checker or color_map to the pigment.
What is it about the nature of height_fields that causes this?


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From: Warp
Subject: Re: height_fields
Date: 4 Sep 2002 20:53:06
Message: <3d76aaf2@news.povray.org>
klotera <klo### [at] hotpopcom> wrote:
> I have a question about height_fields.. i just learned them the other night
> and I have been trying to do different texture options with them (the
> actual height-field object, not the reference image) and i've foud I cant
> do alot of things, like apply apply a checker or color_map to the pigment.
> What is it about the nature of height_fields that causes this?

  It would help if you posted a short code which you are trying to make
work and you explained what are you expecting and what it's doing wrong.
From your description alone it's difficult to tell what are the problems
you are having.

-- 
#macro N(D)#if(D>99)cylinder{M()#local D=div(D,104);M().5,2pigment{rgb M()}}
N(D)#end#end#macro M()<mod(D,13)-6mod(div(D,13)8)-3,10>#end blob{
N(11117333955)N(4254934330)N(3900569407)N(7382340)N(3358)N(970)}//  - Warp -


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From: hughes, b 
Subject: Re: height_fields
Date: 4 Sep 2002 21:33:16
Message: <3d76b45c@news.povray.org>
A question of scale, perhaps? That's the only thing I can think of that 
might be the problem. If the HF is left unit-sized, as well as any 
pattern such as checker or a gradient y then they will equal each other. 
Although for any other pattern besides checker I'd expect you could see 
at least something of it on the HF.
height_field is definitely texturable like most everything else.


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From: Christopher James Huff
Subject: Re: height_fields
Date: 4 Sep 2002 22:56:30
Message: <chrishuff-6CC02E.22555204092002@netplex.aussie.org>
In article <web.3d769f5626cc84be295e176c0@news.povray.org>,
 "klotera" <klo### [at] hotpopcom> wrote:

> I have a question about height_fields.. i just learned them the other night
> and I have been trying to do different texture options with them (the
> actual height-field object, not the reference image) and i've foud I cant
> do alot of things, like apply apply a checker or color_map to the pigment.
> What is it about the nature of height_fields that causes this?

Textures for height fields work just like textures for any other object. 
The thing that seems to be causing you trouble is that POV-Ray textures 
are solid: the texture is evaluated at each point in space, not at UV 
coordinates on a surface. The checkers pattern is a 3D grid of cubes, so 
simply applying a checkered texture to a height field won't give squares 
on the surface, the height field will rise and fall through the cubes. 
Applying the texture to a sphere will make this clear.

You could unevenly scale the checkers pattern to be larger along the y 
axis, so the height field stays within one "layer" of cubes, or you 
might be able to do something with the UV mapping feature. (I haven't 
done anything with this feature myself, so I'm not sure if it is 
applicable here)

Color maps don't apply to the checkers pattern or any other block 
pattern, you need to use something like bozo or crackle. If this wasn't 
what you meant, I don't understand...color maps behave the same for any 
texture, whether it is applied to a height field or not.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/


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