Op 22/12/2019 om 02:14 schreef AndreyG:
> Thank you for your explanation Thomas,
> 
> So you are saying in real life if I place glass perpendicularly to Sun rays and
> camera axis will be perpendicular to glass surface there always be reflection?
> (Can not do experiment it is raining for a week in Vancouver! :).

Real life is not raytracing! and I cannot answer you for the real life 
situation (I leave that to my betters). But I guess that you better not 
look into the glass in such a set-up if you want to keep your vision 
intact. ;-)

> 
> I am total newbe with Povray trying to make sense of it.
> I have another question can not grasp.
> I make simplest geometry: camera and spotlight.
> Spotlight points at camera, camera looks at spotlight.
> For whatever reason camera does not see the light.
> https://imgur.com/a/xeJ3Ykm
> Can't find what i am doing wrong.
> 

Again, raytracing does not work exactly like real life. A spotlight or 
any light in POV-Ray, is not physically "shinning" like a lamp, it needs 
an object to shine upon, and a camera, by itself, is not an "object" 
either. Well, I hope I tell this right; if not, someone will correct me 
I am sure.

Try this:

//--------------------------------------------------------
#version 3.7;

global_settings {
   assumed_gamma 1.0
}

// perspective (default) camera
camera {
   location  <0.0, 0.0, -10.0>
   look_at   <0.0, 0.0,  0.0>
   right     x*image_width/image_height
   angle 70
}

// create a point "spotlight" (conical directed) light source
light_source {
   <200, 100, 100>
   color rgb <1,1,1>
   spotlight
   point_at <0, 0, 0>
   radius 50
   tightness 5
   falloff 8
}

// linear prism in z-direction: from ,to ,number of points (first = last)
prism {
   -1.00 ,1.00 , 6
   <-1.00, 0.00>,  // first point
   < 1.00, 0.00>,
   < 1.00, 1.00>,
   < 0.00, 2.00>,
   <-1.00, 1.00>,
   <-1.00, 0.00>   // last point = first point!!!!
   rotate<-90,0,0> scale<1,1,-1> //turns prism in z direction! Don't 
change this line!

   texture {pigment{ color rgb 1 }}

   scale <1.00,1.00,1.00>
   rotate <0,30,0>
   translate <0.00,0.00,0.00>
} // end of prism //--------------------------------------------------------

If you are new to POV-Ray, I suggest you read carefully the 
documentation (I know! it is huge but it is worthwhile!) and play with 
the many example scenes given. You will discover that a new world and 
new insights will be revealed to you :-)

http://wiki.povray.org/content/Main_Page

And of course, do not hesitate to call here. We are a helpful bunch of 
guys/girls (not heard much of the latter unfortunately...)

-- 
Thomas

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