Can't get mesh lights to stop casting shadows

[Anonymous]

The first image shows three objects used as mesh lights to represent particle beams. There is a standard surface material with emission applied to make them visible. The problem is that they cast shadows, which they should not.

In the second image, I've turned off the lights on two of the beams, leaving them to cast light only through standard surface emission. The light on the third one is still on.

The Arnold Properties modifier is applied to all three beams and is set to all casts shadows, receives shadows, and self-shadows off. Furthermore, I've also tried adding Arnold properties to the Arnold Lights with the same settings, and tried with Arnold Properties on both lights and meshes.

The result is that using these objects as mesh lights makes them cast shadows regardless of the Arnold Properties settings. What can I do to fix this?

[lee_griggs]

If you don't want them to cast shadows then why even use mesh lights? Won't emission work on its own?

cast_shadows seems to work for me using the scene on the mesh_light page.

It might be easier to test with disable shaders in the diagnostics or use debug > lighting?

[Anonymous]

The flare on the mesh lights is brighter, with less noise per sample. I can see the result you've posted, but that's not exactly what I want--I must not have expressed myself correctly. The shadows the beams are creating on the slab are being cast by another light.

[Stephen.Blair]

The mesh used for a mesh light will cast shadows, because lights have to be visible to shadow rays.

[Anonymous]

Well, alright. Can I exclude the mesh via light groups or similar?

[madsd]

Yes, use an arnold properties modifier and exlude the lamp needed.

I reproduced your case and have total control over the meshlights shadows from this secondary light.
I know how you rigged your scene and you have an external light shining at the meshlight mesh, you want to turn this shadow off.