Im am still a novice with povray, which means i dont understand a lot 
about povray. How do i go about creating a rough surface (for example 
the randomness/roughness of the surface of a rock). From what i have 
read so far I can use an isosurface to achieve this, or is there 
something else that will work better.

If isosurface is the way to go how can i apply it to a object that i 
have declared / created?

Regards
Martin.

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Try this

Mick

"Marty" <1@1.1> wrote in message news:40dfb452$1@news.povray.org...
> Im am still a novice with povray, which means i dont understand a lot
> about povray. How do i go about creating a rough surface (for example
> the randomness/roughness of the surface of a rock). From what i have
> read so far I can use an isosurface to achieve this, or is there
> something else that will work better.
>
> If isosurface is the way to go how can i apply it to a object that i
> have declared / created?
>
> Regards
> Martin.

Post a reply to this message

Attachments:
Download 'Rock tezst.pov.txt' (3 KB)

> Im am still a novice with povray, which means i dont understand a lot
> about povray. How do i go about creating a rough surface (for example
> the randomness/roughness of the surface of a rock).

The question is, do you need something which is truly rough, or can you
settle for something which only *looks* rough?

If you only need a small amount of roughness, you can make an otherwise
smooth surface *appear* rough by adding a normal{} to it. This has the
advantage of keeping the modelling simple while still making an object that
looks detailed. It has the disadvantage that the object's shadow is still
smooth, and the fake bumps don't really protrude from the object. But
sometimes it's good enough, and it's definitely easier for a beginner.

If this will work for you, then you should look up "normal" in the
documentation, or look for it in the tutorial in the documentation's
contents.

 - Slime
 [ http://www.slimeland.com/ ]

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Thanks for the point in an easier direction, but what i am after is a 
very tight rough surface, the kind that you normally get with sand stone 
or granite.

Thanks
Martin.

Slime wrote:
>>Im am still a novice with povray, which means i dont understand a lot
>>about povray. How do i go about creating a rough surface (for example
>>the randomness/roughness of the surface of a rock).
> 
> 
> The question is, do you need something which is truly rough, or can you
> settle for something which only *looks* rough?
> 
> If you only need a small amount of roughness, you can make an otherwise
> smooth surface *appear* rough by adding a normal{} to it. This has the
> advantage of keeping the modelling simple while still making an object that
> looks detailed. It has the disadvantage that the object's shadow is still
> smooth, and the fake bumps don't really protrude from the object. But
> sometimes it's good enough, and it's definitely easier for a beginner.
> 
> If this will work for you, then you should look up "normal" in the
> documentation, or look for it in the tutorial in the documentation's
> contents.
> 
>  - Slime
>  [ http://www.slimeland.com/ ]
> 
>

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"Marty" <1@1.1> wrote in message news:40e00740@news.povray.org...
> Thanks for the point in an easier direction, but what i am after is a
> very tight rough surface, the kind that you normally get with sand stone
> or granite.

Hey Marty (Martin), I replied to you in p.n. and since then have looked for
some info about predeclared objects in isosurfaces. Mike Williams'
Isosurface Tutorial helps explain a bit about that:

http://www.econym.demon.co.uk/isotut/dont.htm

For easy roughness texturing... and I do mean easiest... the 'crand'
keyword, used in a finish statement, can add a sandpaper effect all by
itself. A value of 1 is really extreme, with 0.1 being mild. Tends to be
unusable in animations, it's so random.

Like was already mentioned, just a normal statement -- as in normal {
granite 1 scale 0.1 } -- can do okay if you don't need the object surfaces
actually changed from their usual smooth, textureless form. You'll need the
depth value and scale to suit your object though.

-- 
Bob H.
http://www.3digitaleyes.com

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Thanks for the tips I managed to get the effect of what i wanted by using:

   texture { T_Gold_2A normal { granite 0.1 scale 0 } }
   finish { reflection 1 phong 0.1 }

Regards
Martin.

Hughes, B. wrote:
> "Marty" <1@1.1> wrote in message news:40e00740@news.povray.org...
> 
>>Thanks for the point in an easier direction, but what i am after is a
>>very tight rough surface, the kind that you normally get with sand stone
>>or granite.
> 
> 
> Hey Marty (Martin), I replied to you in p.n. and since then have looked for
> some info about predeclared objects in isosurfaces. Mike Williams'
> Isosurface Tutorial helps explain a bit about that:
> 
> http://www.econym.demon.co.uk/isotut/dont.htm
> 
> For easy roughness texturing... and I do mean easiest... the 'crand'
> keyword, used in a finish statement, can add a sandpaper effect all by
> itself. A value of 1 is really extreme, with 0.1 being mild. Tends to be
> unusable in animations, it's so random.
> 
> Like was already mentioned, just a normal statement -- as in normal {
> granite 1 scale 0.1 } -- can do okay if you don't need the object surfaces
> actually changed from their usual smooth, textureless form. You'll need the
> depth value and scale to suit your object though.
>

Post a reply to this message

> scale 0

"scale 0" means "make this infinitely small." Since this isn't really
possible, POV-Ray is ignoring it. It is probably also giving you warnings
like "Illegal value: Scale X by 0.0. Changed to 1.0." In effect, you could
remove the "scale 0" and it should have no effect on your scene.

 - Slime
 [ http://www.slimeland.com/ ]

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