POV-Ray : Newsgroups : povray.newusers : Re: Noob: Texture rendering as a single color Server Time
30 Jul 2024 06:20:17 EDT (-0400)
  Re: Noob: Texture rendering as a single color (Message 1 to 3 of 3)  
From: Barton Bosch
Subject: Re: Noob: Texture rendering as a single color
Date: 22 Oct 2004 01:10:00
Message: <web.417894c47b3a0cc3e5c79a730@news.povray.org>
Ok, I'll breach etiqutte and reply to my own post, <g>.  I've been doing
some serious RtFMing for the last couple of days and I managed to figure
this one out.

The problem here is that it is impossible to use textures more complex than
simple colors without a UV map (for fellow noobs this is the translation of
3D coordinates to 2D space, hence u, v as in u, v, x, y, z).  It is
possible to do this in PoseRay though the interface implementation isn't
especially intuitive.  On the Geometry - UV tab there is a drop down
window with 5 options for remapping the UV coordinates.  Apparently 'cubic'
is usually best for creating a new UV map.  After selecting the type of UV
map, click the update button (near the upper left corner) and the map will
be generated.

Once this is done the UV coordinates will be added when the .obj or .pov
files are exported and complex textures can be used with your mesh model.
Happy 3Ding.


Ciao,

Barton


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From: Warp
Subject: Re: Noob: Texture rendering as a single color
Date: 22 Oct 2004 04:33:18
Message: <4178c5ce@news.povray.org>
Barton Bosch <bar### [at] yahoocom> wrote:
> Ok, I'll breach etiqutte and reply to my own post, <g>.

  Just curious: How is that breaching etiquette? I have never heard that.

> The problem here is that it is impossible to use textures more complex than
> simple colors without a UV map

  Aren't you confusing textures with image maps?

  It's perfectly possible, easy and feasible to use POV-Ray textures without
UV-mapping, for example to create objects made of wood, marble, rusty iron,
etc.
  Textures using image maps are often too restrictive without UV-mapping.

-- 
#macro M(A,N,D,L)plane{-z,-9pigment{mandel L*9translate N color_map{[0rgb x]
[1rgb 9]}scale<D,D*3D>*1e3}rotate y*A*8}#end M(-3<1.206434.28623>70,7)M(
-1<.7438.1795>1,20)M(1<.77595.13699>30,20)M(3<.75923.07145>80,99)// - Warp -


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From: Mike Williams
Subject: Noob: Texture rendering as a single color
Date: 22 Oct 2004 04:48:38
Message: <Y6DqgCALkMeBFwOR@econym.demon.co.uk>
Wasn't it Barton Bosch who wrote:
>
>Ok, I'll breach etiqutte and reply to my own post, <g>.  I've been doing
>some serious RtFMing for the last couple of days and I managed to figure
>this one out.
>
>The problem here is that it is impossible to use textures more complex than
>simple colors without a UV map

That is not the case.

I can believe that adding UV mapping solved your problem, but it
certainly is possible to apply complex textures without a UV map.

My first guess would be that somehow you ended up with the "uv_mapping"
keyword in your something_pov.inc file without any "uv_vectors" or
"uv_indices". This would tell POV to use UV mapping but all the points
would be uv_mapped to <0,0>.

My second guess would be that it's a problem of scale. Some 3d programs
tend to work with very large or very small object scales. When PoseRay
converts such files it positions the camera at a distance that
corresponds to the scale. You may not realize that your car is, say,
0.01 pov-units long because your camera is placed 0.03 pov units away
from it. Over such a small scale, the Rusty_Iron texture looks like a
single colour, so you have to apply texture {Rusty_Iron scale 0.01}
See this example of unscaled Rusty_Iron, and then see what happens when
you scale the texture or change the value of R.

global_settings {assumed_gamma 1.0}
light_source {<-30, 100, -300> color rgb 1}
#include "textures.inc"
                         
#declare R=0.01;                         
                         
camera {location -z*R*3 look_at <0,0,0>}
sphere {0,R
  texture {Rusty_Iron scale 1}
}

-- 
Mike Williams
Gentleman of Leisure


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