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Grey issue with glass with an inner part

8 REPLIES 8
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Message 1 of 9
julien_modde
207 Views, 8 Replies

Grey issue with glass with an inner part

2353-compare-shadow.jpg

2354-compare-03.jpg

2355-compare-inside.jpg

8 REPLIES 8
Message 2 of 9
julien_modde
in reply to: julien_modde

despite increasing the value of transmission and already being at 16 I still have this grey part on the bottom part where it shouldn't. I've posted 2 separated images showing the difference with and without the glass. What can I do to avoid this grey feeling when th gold part is inside?

Message 3 of 9

Did you also increase the total ray depth ?

Message 4 of 9
lee_griggs
in reply to: julien_modde

What happens when you enable Caustics?

Lee Griggs
Arnold rendering specialist
AUTODESK
Message 5 of 9
julien_modde
in reply to: julien_modde

Hi folks, thx for your answers, in both cases no changes at all 😕

Message 6 of 9
maxtarpini
in reply to: julien_modde

Transmission depth should not be kind of arbitrary. For example here you should go with 8 as depth .. ie. 4 layers of glass geometry need to be passed through in and out .. so it's 4x2.

However what you're seeing there as a gray part are actually reflections. So you need to increase accordling 'specular depth'. Here as above for transmission you ain't gonna crank up specular depth arbitrarly... ie. ask yourself, - how many sheet of geo glass the inner gold reflections need to pass through to reach the image plane (aka eyes) ? Exactly 2 in/out 2x2=4. ( For other camera setups .. think about the floor material if your camera angle goes 45° with the glass obj .. it has to pass the bottom glass but also the side glass before reaching your eyes .. so you have 4x2 depth in that case.. ie. 8 as specular depth ).

Eventually check for Opaque flag, total ray depth and caustics enabled.

-> (no env map) glass-depth.zip

2356-glass-depth.jpg

Message 7 of 9
julien_modde
in reply to: maxtarpini

In your case, you also miss the reflection in the bottom part so what should be increased then?

Message 8 of 9
maxtarpini
in reply to: julien_modde

ain't really missing any reflections.. it's the white floor reflections. just horrible comp and camera angle 🙂

2359-glass-depth2.jpg


This is when your reflections don't have enough depth to reach back the sensor/image/eye plane.

2360-glass-depth3.jpg

Message 9 of 9
ddankhazi
in reply to: julien_modde

You may have a surface normal issue. In some cases you can't see the flipped normals in Maya's viewport (make sure the Two Sided Lighting is turned off in the viewport). Try to flip (reverse) the normals for that particular object (or geo shell).
Mesh Display -> Reverse.
Cheers, D

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