Blackbody emission and one poligon face issue

[dotcommer]

Check the screenshots.

I've noticed that if I have an emission from an alpha channel, it looks correct but only from one side. If I were to flip that single polygon face over, I can see the cutout of the alpha, but no blackbody emission. Why is that? Notice in the renders that the surface below the UI is very reflective, so we should be seeing a reflection, but in the first image, you can't. In the second, I've flipped the image over 180˚, and now you can see a reflection, but notice the "top" (was the bottom of this polygon face) is very dim. Is there something I'm not doing correctly in my emission texture?

Using Octane v2.04.1 / C4D R15

[aoktar]

yes, it casts the illumination from front side

[dotcommer]

Is there a way to cast from both sides? My only work-around has been to duplicated the layer, flip it 180˚ and put it slightly below the original.

[shawnfrueh]

Is there a way to cast from both sides? My only work-around has been to duplicated the layer, flip it 180˚ and put it slightly below the original.

Try using a mix material, put the emission material in both slots and use 'side' as the mix. This should add the material to the front and back of the polygons.

[dotcommer]

use 'side' as the mix. This should add the material to the front and back of the polygons.

What do you mean? I'm not seeing anything like that in the mix material. Just two slots for two materials, and the amount is set to a floatTexture.

[aoktar]

This is how the work Octane. Use a thin box rather than plane. You and all guys should look to standalone topics at least sometimes.

[dotcommer]

Ah, thank you ahmet. The thin box works perfectly.