Subsurface scattering does not support transmittance.

[djrm]

Operating system or device, Godot version, GPU Model and driver (if graphics related):
Fedora 26, Nvidia Proprietary 384.69 bc005a5

Issue description:

SSS does not support transmittance, here is the SSS demo from sketchfab

does not look really nice, but it lets light through thinner parts of the object,

here is how it looks in godot

ping @reduz

Steps to reproduce:

Link to minimal example project:

[reduz]

What you are looking for is transmittance, which is unsupported. It needs to be added eventually (still thinking how to do it)

…

On Sep 18, 2017 5:08 PM, "Daniel Ramirez" ***@***.***> wrote: *Operating system or device, Godot version, GPU Model and driver (if graphics related):* Fedora 26, Nvidia Proprietary 384.69 bc005a5 <bc005a5> *Issue description:* SSS does not really look like it, it makes things look like waxs, but it does not seem to let light through, for example here is how it looks in sketchfab [image: screenshot from 2017-09-18 14-57-13] <https://user-images.githubusercontent.com/1103897/30561878-2c5865fe-9c82-11e7-8749-704953d81abe.png> does not look really nice, but it lets light through thinner parts of the object, here is how it looks in godot [image: screenshot from 2017-09-18 15-04-57] <https://user-images.githubusercontent.com/1103897/30562079-e5a8410a-9c82-11e7-8a63-3fed996617f5.png> [image: screenshot from 2017-09-18 15-05-43] <https://user-images.githubusercontent.com/1103897/30562086-e9295210-9c82-11e7-8d83-87da2c36e478.png> it has almost all the SSS paramter (.95), i remember it used to be better but i could never get the same type of result as the sketchfab one. *Steps to reproduce:* *Link to minimal example project:* — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#11398>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AF-Z2_417-pS7GTskMEQX7rYS2stBTT_ks5sjs2lgaJpZM4PbdN2> .

[djrm]

@reduz oh, nice, will change the title then

[reduz]

The problem is that, for transmittance to work, shadow mapping needs to be enabled and objects recieving it need to have culling set in reverse (which could be automatized I guess). As the effect happens by measuring the object thickness via shadow map..

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On Sep 18, 2017 5:41 PM, "Daniel Ramirez" ***@***.***> wrote: @reduz <https://github.com/reduz> oh, nice, will change the title then — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#11398 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AF-Z25T9hdB2RjvAd_npz0h08HLaNi0Tks5sjtWFgaJpZM4PbdN2> .

[djrm]

@reduz yeah i remember reading something like that once, so i was wondering why godot does not ask for a cusom SSS texture, but yeah also saw techniques for generating it.

[reduz]

Maybe saketchfab uses a transmittance map?

[djrm]

reduz the gltf i downloaded does not have any texture, here it is.

stanford_dragon_sss_test.zip

[Pseudopode]

Isn't it possible to use the old trick of dual pass rendering ?
First pass = render backfaces, largest distance from the camera
Second Pass = render frontfaces, closest to the camera
Distance = 2nd Pass - 1st Pass

It's not true for concave objects, but it's a close approximation for real-time