R help - Nov 2008 - rgl lighting question

Hi, I'm using rgl to generate a 3D surface plot and I'm struggling to  
get the lighting correct. Currently the surface gets plotted, but is  
very 'shiny'. On rotating the view, I get to see parts of the surface  
- but overall I don't see much detail because of the spotlight like  
lighting.

I've played around with the specular, ambient and diffuse but I can't  
bring out the details of the surface. Could anybody point me to some  
examples of how to make a plain matte surface, which isn't obscured  
by specular reflections?

Thanks,

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Rajarshi Guha  <rguha at indiana.edu>
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If you don't get a good night kiss, you get Kafka dreams."
                 -Hobbes

2008/11/21 Rajarshi Guha <rguha at indiana.edu>:
> Hi, I'm using rgl to generate a 3D surface plot and I'm struggling
to get
> the lighting correct. Currently the surface gets plotted, but is very
> 'shiny'. On rotating the view, I get to see parts of the surface -
but
> overall I don't see much detail because of the spotlight like lighting.
>
> I've played around with the specular, ambient and diffuse but I
can't bring
> out the details of the surface. Could anybody point me to some examples of
> how to make a plain matte surface, which isn't obscured by specular
> reflections?
 Have you tried lit=FALSE? This sphere is so unspecular it appears flat:

 > spheres3d(0,0,0,color="red",lit=FALSE)

Barry

On 21/11/2008 2:30 PM, Rajarshi Guha wrote:
> Hi, I'm using rgl to generate a 3D surface plot and I'm struggling
to
> get the lighting correct. Currently the surface gets plotted, but is  
> very 'shiny'. On rotating the view, I get to see parts of the
surface
> - but overall I don't see much detail because of the spotlight like  
> lighting.
> 
> I've played around with the specular, ambient and diffuse but I
can't
> bring out the details of the surface. Could anybody point me to some  
> examples of how to make a plain matte surface, which isn't obscured  
> by specular reflections?
This gives the regular shiny surface:

library(rgl)
example(surface3d)

This gives one with no specular reflections, because the material 
doesn't do that:

open3d()
surface3d(x, y, z, color=col, back="lines",
specular="black")

And here's another way to get no specular reflections.  This time 
there's no light to reflect that way:

open3d()
rgl.pop("lights")
light3d(specular="black")
surface3d(x, y, z, color=col, back="lines")

I suspect you missed the rgl.pop() call.  If you just call light3d or 
rgl.light() you'll add an additional light, you don't change the 
existing one.

Duncan Murdoch