Color Emission on Material

[antoinebourguelle]

Hi !

I'm a french student and I would like to re-create Loki's Portal, I looked for a technic to only illuminate edges, that will light up my scene. I have connected aiCurvature on Emission : The initial color is orange (image1) but when I increase Multiply (image2) the color turns in Yellow (image3). Do you have solutions to increase brightness without changing color ?

Thank you for your answer !

Have a good day

[mspeer]

Hi!

The color does not change, it's still orange, but your Monitor can't display such high values, with red and green both at max (255 or 1) yellow will be displayed.

I recommend to insert a "clamp" or "aiClamp" node between aiCurvature and the Emission Input, then you can set the max value to "1" or maybe even a bit higher for a glow effect.

[antoinebourguelle]

Thank you for you answer !

I don't really understand the utility and the way it works of the aiClamp Node. I just want emit a lot of light from the edges. It exist a limit of the aiStantardSurface or of materials to emit light ?

[mspeer]

Hi!

No there is no limit.

However when using very high light values change in Render Settings:

Arnold Renderer > Clamping > Indirect Clamping (set to 100 or higher)

Keep in mind that Arnold is a physically correct, so light emission is tight to the color values of a surface.

Maybe it's better to fake the emission with a light.

Here an animated screenshot showing the effect of exposure, color values and light emission, the last image simply uses a orange point light.

[antoinebourguelle]

Thank you for you answer !

I tried your solutionn, to increase Indirect Clamping, from 10 to 100 (image 01). I don't see difference, the render is better quality but the color continue to change (Orange to Yellow),(Image 02) 😞

The real solution is to create fake light ? But on water reflection we will don't see the roughness of portal ...

Another solution ?

[mspeer]

Hi!

I have no idea what the problem is.

If you use a more bright color than orange you get yellow, so use a lower color value, it doesn't matter if you lower the color or decrease overall brightness, check my screenshot again to see how color comes back with lower color values.

"But on water reflection we will don't see the roughness of portal"

- What roughness?

Please describe more detailed what the problem is.

Do you want to light the environment or are only reflections important?

In other words, do you need a high emission value or a high multiply value?

a) High multiply value: Solution = clamping

b) High emission value: Solution = fake light

You can achieve every possible effect with these 2 options.