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Maniphest T50485

SSS stop the light at scale as it was a distance
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Description

I was thinking about the SSS scale as an attenuation scale but it looks that any light no matter how strong it is can't pass through the object.
Perhaps a mode where the scale is given for a light strength , For example it stops a 1.0 watt ray after 1.0 cm but a 2.0 watt ray should pass half.

I don't know if it's a bug or not but I'm pretty sure SSS don't behave like that in real life, this implementation doesn't follow the conservation of energy

Example in the screenshot, note the 1000000.0 light intensity and the sss scale at half the object's width

Event Timeline

kevin deguisne (iscream) created this task.Jan 20 2017, 2:31 PM
Lukas Stockner (lukasstockner97) changed the task status from Unknown Status to Archived.Jan 22 2017, 9:15 PM
Lukas Stockner (lukasstockner97) claimed this task.
Lukas Stockner (lukasstockner97) added a subscriber: Lukas Stockner (lukasstockner97).

This isn't a bug, SSS behaves exactly as it's supposed to.

The confusion here comes from SSS being an approximation of Volume Scattering. If you use a volumetric scattering shader setup on the object, light will pass through.
SSS approximates that effect, by essentially moving the shading point a bit before calculating lighting. This makes it a lot faster than true scattering, but has some limitations - light doesn't scatter between objects, and doesn't pass through it onto other objects. This isn't something that can be fixed, unfortunately.