What is the effect of scaling on subsurface values? Are they scaled accordingly
in order to keep the material equivalent (IMO, a half sized wax object is still
made of the same wax with same SSLT characteristics)? If so, what is the
corresponding law? Related to volume?


Bruno

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> What is the effect of scaling on subsurface values? Are they scaled accordingly
> in order to keep the material equivalent (IMO, a half sized wax object is still
> made of the same wax with same SSLT characteristics)? If so, what is the
> corresponding law? Related to volume?
>
>
> Bruno
>
>

Those values must NOT be affected by scaling, as it would change the 
characteristics of the material.
They are thus treated just like media and fading interiors. Scaling 
don't affect the density of your media, the fade_distance, the ior, nor 
the SSLT parameters.

In the case of SSLT, you tweak the effect using mm_per_unit in the 
global_settings, defaulting to 10 => assumes that 1 unit = 1 cm.
If you model using 1 inch per unit, set it to 25.4.
If you model using 1 unit = 1m, set it to 1000.
If you model using units corresponding to a larger length, SSLT becomes 
insignificant and should probably not be used.



Alain

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Alain <aze### [at] qwertyorg> wrote:

>
> Those values must NOT be affected by scaling, as it would change the
> characteristics of the material.


Okay, but isn't it the case that a set of conditions that look great for
portions of an object which are really "thick" end up giving ugly results for
portions that are "thin".  Thus, I imagine good conditions for a big candle
could look ugly for a significantly smaller one.

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> Alain<aze### [at] qwertyorg>  wrote:
>
>>
>> Those values must NOT be affected by scaling, as it would change the
>> characteristics of the material.
>
>
> Okay, but isn't it the case that a set of conditions that look great for
> portions of an object which are really "thick" end up giving ugly results for
> portions that are "thin".  Thus, I imagine good conditions for a big candle
> could look ugly for a significantly smaller one.
>
>
>

True.
Just remembre that the current implementation is only in it's alpha 
stage and subect to importent changes in the future.



Alain

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Am 17.02.2011 00:25, schrieb Bruno Cabasson:
> What is the effect of scaling on subsurface values? Are they scaled accordingly
> in order to keep the material equivalent (IMO, a half sized wax object is still
> made of the same wax with same SSLT characteristics)?

Yes, if you will. (Actually, what's really going on is more like media: 
The effect depends on the absolute distances involved. So strictly 
speaking, in order to keep the material equivalent the values are /not/ 
scaled.)

> If so, what is the
> corresponding law? Related to volume?

No, related to distance.

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Am 17.02.2011 03:49, schrieb gregjohn:
> Alain<aze### [at] qwertyorg>  wrote:
>
>>
>> Those values must NOT be affected by scaling, as it would change the
>> characteristics of the material.
>
>
> Okay, but isn't it the case that a set of conditions that look great for
> portions of an object which are really "thick" end up giving ugly results for
> portions that are "thin".  Thus, I imagine good conditions for a big candle
> could look ugly for a significantly smaller one.

Yes, that /may/ happen - but remember that a smaller candle /does/ look 
different to a larger one when photographed and then scaled to match, 
with the light appearing to "bleed" deeper into the wax in the smaller 
candle (relative to the candle's total size).

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