[Radiance-general] Reflection vs specularity

[atelier iebele abel]

Hi Giulio,

Changing -sj did not resolve the problem (already tried that) , and 
photoshop is not a solution since it has to be an animation on video.
Plus it should be more or less physically correct...

I just return from an example site, where I have have seen an example 
of  the floor material in a real situation (natural wood finished with a 
wax coating).
This floor type does reflect its environment really smoothly but does 
not reflect lightsources really hard. In other words, it seems that in 
the real life example there is never a direct reflection from the 
lightsources/lightbeam  to the eye. The reflection seems too diffuse for 
that to happen.
So, in the real world the situation I like to simulate exists, now 
finding a way to simulate this in Radiance will be the challenge..

I am reading the book RWR now,  chapter 12.1 on specular sampling in 
indirect calculations. However I have the feeling that the problem i am 
facing is in the direct calculation. It just seems that when I could 
control the highlight apart from the reflection , I could model my floor 
more accurate.
Or am I totaly lost here ??  Is specularity exactly the same as 
reflection in Radiance?? After 10 years I still have to learn soo much 
about Radiance. Ok,  that's the fun and the power of Radiance... :)
Any suggestions remain welcome.

Iebele


Giulio Antonutto wrote:

>Iebele,
>have you tried with -sj, just to jitter the specular component?
>
>an alternative trick is to generate just an image without specular
>component
>and another one with it (you may use lower settings for this, may be
>just -av something something something -ab 0).
>then photoshop will help doing the trick... but I wouldn't define it a
>physically accurate technique :-)
>
>ciao
>giulio
>
>
>
>
>-----Original Message-----
>From: radiance-general-bounces at radiance-online.org
>[mailto:radiance-general-bounces at radiance-online.org] On Behalf Of
>atelier iebele abel
>Sent: 20 July 2005 12:39
>To: Radiance general discussion
>Subject: [Radiance-general] Reflection vs specularity
>
>Hi,
>
>I have a problem modelling a reflective floor of a large museum hall. 
>The specular and roughness components (0.08 and 0.01) in the material of
>
>the floor  result in smooth reflections of the walls, paintings, windows
>
>etc.
>The problem arises when adding some lightsources. The lightsources cause
>
>specular reflections with very bright specular spots (highlights) on the
>
>floor. These specular spots do not look realistic (better said: these 
>highlights disturb in the image, because there are so many of them).
>I have tweaked the specular, roughness and rendering parameters also, 
>but I can't  get rid of these specular reflection highlights, apart from
>
>making the roughnes very small or 0. But with low or zero rougness the 
>relections of the other geometry become too sharp.
>Is there a way to model a reflective material (or lightsource?) without 
>a ( or a dimmed) specular reflection highlight ?
>Or any other suggestion?
>
>Iebele
>
>
>
>
>
>_______________________________________________
>Radiance-general mailing list
>Radiance-general at radiance-online.org
>http://www.radiance-online.org/mailman/listinfo/radiance-general
>
>_______________________________________________
>Radiance-general mailing list
>Radiance-general at radiance-online.org
>http://www.radiance-online.org/mailman/listinfo/radiance-general
>
>
>  
>