hi,

clipka <ano### [at] anonymousorg> wrote:
> Am 08.09.2018 um 13:45 schrieb jr:
> > now I would like to find out how to increase the translucence of the rhomboids.
>
> Are you aiming for semi-transparency or diffuse translucency?

translucent I guess.  I replaced (in BGimeno's code) the rgb colour returned
from  the CW_angle macro with a rgbt (with fixed .45 transmit, see image) but
that results in increased transparency.  the effect I'd like to achieve is more
like very, very thin mother-of-pearl.


regards, jr.

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hi,

"B. Gimeno" <nomail@nomail> wrote:
> > now I would like to find out how to increase the translucence of the rhomboids.
> >
> > regards, jr.
>
> Look in the last line of the CW_angle macro, I deactivated the values
> ​​of transparency and filters to avoid warning messages.
> The code is a little clumsy and needs many fixes to avoid duplicate code here
> and there. Patience.

thanks.  I put a '#debug concat' inside the macro and found that both filter +
transmit stayed at 0.0 throughout.  that led me to use a (fixed) transmit value
as part of a 'rgbt' colour.  see reply to clipka for image.

> BGimeno
>
> Pd. Don't call them rhomboids, they are squares subjected to great tension. Very
> sensitive polygons.

:-)  "square" too is full of connotations, how about "retro oblong"?  ;-)


regards, jr.

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Am 09.09.2018 um 18:50 schrieb jr:
> hi,
> 
> clipka <ano### [at] anonymousorg> wrote:
>> Am 08.09.2018 um 13:45 schrieb jr:
>>> now I would like to find out how to increase the translucence of the rhomboids.
>>
>> Are you aiming for semi-transparency or diffuse translucency?
> 
> translucent I guess.  I replaced (in BGimeno's code) the rgb colour returned
> from  the CW_angle macro with a rgbt (with fixed .45 transmit, see image) but
> that results in increased transparency.  the effect I'd like to achieve is more
> like very, very thin mother-of-pearl.

Then - presuming your torus thingumajig is using non-solid geometry -
you want backside diffuse illumination, and maybe one or two more levels
of radiosity recursion.

To enable backside diffuse illumination, use the two-parameter version
of `diffuse`:

    finish { diffuse FRONT,BACK }

where FRONT is how much light is reflected to the illuminated side, and
BACK is how much light is transmittend to the other side. The sum should
be smaller than than 1.0 for realistic materials.

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Le 18-09-09 à 13:08, clipka a écrit :
> Am 09.09.2018 um 18:50 schrieb jr:
>> hi,
>>
>> clipka <ano### [at] anonymousorg> wrote:
>>> Am 08.09.2018 um 13:45 schrieb jr:
>>>> now I would like to find out how to increase the translucence of the rhomboids.
>>>
>>> Are you aiming for semi-transparency or diffuse translucency?
>>
>> translucent I guess.  I replaced (in BGimeno's code) the rgb colour returned
>> from  the CW_angle macro with a rgbt (with fixed .45 transmit, see image) but
>> that results in increased transparency.  the effect I'd like to achieve is more
>> like very, very thin mother-of-pearl.
> 
> Then - presuming your torus thingumajig is using non-solid geometry -
> you want backside diffuse illumination, and maybe one or two more levels
> of radiosity recursion.
> 
> To enable backside diffuse illumination, use the two-parameter version
> of `diffuse`:
> 
>      finish { diffuse FRONT,BACK }
> 
> where FRONT is how much light is reflected to the illuminated side, and
> BACK is how much light is transmittend to the other side. The sum should
> be smaller than than 1.0 for realistic materials.
> 

For mother-of-pearl, you also need a fair amount of iridescence. Maybe 
something in the 0.4 .. 0.6 range.

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hi,

clipka <ano### [at] anonymousorg> wrote:
> Am 09.09.2018 um 18:50 schrieb jr:
> > ... like very, very thin mother-of-pearl.
>
> Then - presuming your torus thingumajig is using non-solid geometry -

"my" torus.  lol.  I would not be able to create anything like it -- if my life
depended on it.

> you want backside diffuse illumination, and maybe one or two more levels
> of radiosity recursion.
> To enable backside diffuse illumination, use the two-parameter version
> of `diffuse`:
>     finish { diffuse FRONT,BACK }
> where FRONT is how much light is reflected to the illuminated side, and
> BACK is how much light is transmittend to the other side. The sum should
> be smaller than than 1.0 for realistic materials.

only had one quick try so far (got a bit paranoid last night when the CPU temp



Alain <kua### [at] videotronca> wrote:
> For mother-of-pearl, you also need a fair amount of iridescence. Maybe
> something in the 0.4 .. 0.6 range.

thanks.  I'll add this "into the mix" next run.


regards, jr.

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