On 12/10/2010 10:11 PM, Bidski wrote:
> Jim Holsenback <jho### [at] povrayorg> wrote:
>> On 12/10/2010 07:18 PM, Bidski wrote:
>>> One thing that I am noticing is that it spends a lot of time rendering the top
>>> of the gem (the part with the most clarity in Stone1.bmp) and then it chops
>>> through the last part in less than a second (total rendering time is 17
>>> seconds).
>>
>> sounds like you need to play with the angle of light_source and/or camera
> 
> Ok, I have tweaked the camera angle and the light_source angle and have gotten
> some different results (a little better, but still not quite there). I have
> attached a picture of what I have now. (stone4.bmp).
> 
> The camera used to be
> 
> camera
> {
>   location <0, 2.5, -6>
>   look_at <0, 0, 0>
> }
> 
> and is now
> 
> camera
> {
>   location <0, 0, -5>
>   look_at <0, 0, 0>
> }
> 
> and the light_source used to be
> 
> light_source
> {
>   <0, 0, 0>
>   colour rgb <1, 1, 1>
>   translate <65, 65, -65>
> }
> 
> and is now
> 
> light_source
> {
>   <0, 0, 0>
>   colour rgb <1, 1, 1>
>   translate <5, -5 -5>
> }
> 
> Keeping in mind that I have a white  of radius 5 centered on the origin, this
> places the camera and the light source directly on the edge of the sphere.
> 
> Im not really sure how else to twek this now as every tweak I make from here
> returns me to what I had before in stone1.bmp.
> 
> If I turn conserve_energy off it brightens the gem considerably, but doesnt
> change the overall appearance much.
> 
> If I have the following inside a finish
> 
> reflection
> {
>   colour rgb <1, 1, 1>
>   0.1            // What is this number doing?
>   fresnel on
> }
> 
> Regards
> Bidski
> 
> http://i288.photobucket.com/albums/ll167/Bidskii/stone4.jpg
> 

getting there ... try something other than black background ... also I
find it helpful to have object at <0,0,0> with cam at say <0,0,-10> (or
some other suitable -z dir) with look_at <0,0,0> ... rotate x*15 angles
cam up by 15 deg then rotate y*30 goes clock-wise ... similar setup with
light_source that way it's easier (to me anyways) to keep track of where
everything is. besides the texture ... light position and cam position
(viewing angle) are most important aspect of scene setup. seems like
you're headed in the right direction.

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