Can't get lights to work in Arnold Render

[t_smith5]

Hi

I'm currently having problems getting lights to work with Arnold Renderer. I've skimmed over the user guide and tried checking other forum threads, but can't get my head around why they're not working. I've tried adjusting the Intensity and Exposure of the lights, increased the scale of them, moved them into position, but whenever I hit render, it looks to render my scene, but everything is still black. Any ideas? Thanks.

[damaggio]

The larger the scene scale the more intensity you will need , like really large values. That's the same in every renderer.

You did not provide any settings or a scene example so there's not much else to say.

[t_smith5]

I’m trying to render out a character. I’ve set the resolution to 1080p, I’ve set the screen/render area so the character fits within the frame, and I’ve even tried increasing the intensity to maximum (10) and it doesn’t make any difference. I’ve tried a Spot Light and an Area Light, and I can’t get either one to work. Though I did try a Directional Light to begin with and that did work.

[damaggio]

That's a very common mistake with beginners, you should always work in the same scale so everything works correctly including your cameras.

Try larger values 100000

[damaggio]

Provide the scene scale and the set up or the scene file.

[damaggio]

Also make sure you understand the different types of light and how they physically work, there's a reason why a directional light works with a lower value.

[t_smith5]

How do you find out the scene scale? It's a default/new scene anyway. I've just imported the model in. The model comes with a HemisphereLight and PointLight, but rendering just gives me a black screen, even if I increase the Intensity of the PointLight to 10. Also, I've found GPU rendering to be a bit slower than CPU from what I've tested. I've attached the scene file.

[Stephen.Blair]

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@t_smith5 wrote:

How do you find out the scene scale? It's a default/new scene anyway. I've just imported the model in. The model comes with a HemisphereLight and PointLight, but rendering just gives me a black screen, even if I increase the Intensity of the PointLight to 10. Also, I've found GPU rendering to be a bit slower than CPU from what I've tested. I've attached the scene file.

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The HemisphereLight has Type=Point Light

Add a skydome light...

[mspeer · Accepted solution]

Hi!

@damaggio is right, the  intensity values for your lights are way too low.

10 is not the maximum, you can enter any value in the value field, so try 100 000  as suggested (or even higher values).

But there are also some other problems you need to fix first, before you can test different values for light intensity (or Arnold > Exposure, or other light related values in Arnold > ...):

1. The material of your model (MaterialFBXASC046001_tinaFBXASC046tga) is set to 100% reflective and the color multiplication is set to black (0).

Set Specular Shading > Reflectivity to a value < 1, and/or

set Specular Shading > Reflected Color to any other value than black.

or even better assign a new Arnold material.

2. The HemisphereLight is inside your model, move it outside of your object.

[t_smith5]

Okay. That seems to have done the trick. Thank you. 😄 Still need to do a bit of experimenting, but I think I've got it working correctly. Question: if using the Arnold Render, is it best to use an Arnold Material...?

It's quite crazy how high you need to set the Intensity in order to get any decent light and for the model to show in the render... In the scene, with the light bulb selected, the model looks completely washed out by the scene light.

[damaggio]

Yes you need to use Arnold shaders even though Arnold can translate Maya shaders is better to use the native materials, same for Renderman, Vray and Redshift.

This phrase"with the light bulb selected, the model looks completely washed out by the scene light."  has no meaning without an image and the settings.

[damaggio]

Here's a good resource of Arnold tutorials for you by Arvid Schneider.

https://www.youtube.com/channel/UC1KDwEVBlxr4ew7xqLOhu9g

[mspeer]

Hi!

For lighting adjustments you should always rely on the rendered result in the renderer you use, but you can get a much better result in Viewport 2.0 by setting the Decay Rate for the lights to "Quadratic" and/or adjusting other attributes for the lights than Intensity to control the overall brightness.

[t_smith5]

I'm still a bit lost and unsure. At the moment I have a SkyDome in the scene. I don't see any options for Decay Rate. Also, the render is clear, but when I see the screenshot (PNG), it's looking pretty dark. 😕

[mspeer]

Hi!

The SkyDomeLight does not have a settable Decay Rate.

What do you mean with "screenshot"?

Currently I guess the problem is related to Color Management, so you may check for related information about this in the Maya Online Help, the forum and other related entries in the web, there should be plenty of information about Color Management in Maya.

[maisura.1988]

Thanks. This helped me.