sphere shape light use analytics cannot use post volume and light beams

[Colin55]

If sphere lights could utilize light beams, more effects would be achievable.

[skientia]

This is likely intentional.

"Sphere light", in a production context, is uncommon since the emission is unpractical due to its omnidirectional nature.

In "reality", besides the sun, omnidirectional emissive sources are non-existent at the exception of chemoluminescence which aren't utilized as light sources. The artificial "light bulb" sources have a low angle of non-emission (metallic cap part). Rechargeable model shown:

A popular "effect" from a "circular/spherical shape" is "Starburst" (Glare in Octane postFX), but it falls under the optical domain, not volumetric.

more effects would be achievable.

What are those "effects"?

[Colin55]

What are those "effects"?

like this:

I just want to create a glowing sphere with light beams, like those in nightclubs or bars. Using volume fog results in a lot of noise and slower rendering. Fortunately, by adjusting the light spread angle, I achieved a similar effect, though there are still some imperfections when rotating the view

[skientia]

What are those "effects"?

like this:
1a7827a9912003b647483e7e2d9d156.png
I just want to create a glowing sphere with light beams, like those in nightclubs or bars. Using volume fog results in a lot of noise and slower rendering. Fortunately, by adjusting the light spread angle, I achieved a similar effect, though there are still some imperfections when rotating the view

Thank you for providing an example.

Here's the breakdown on how it can occur in reality or in an imaginary world that respects most of the laws of physics:

1. an enclosed object, such as a rock or a disco ball.
2. an emissive source, we could imagine the rock being filled with some sort of magma and the disco ball containing a light bulb within, at the center.
3. the most important part is this third point: separation to let light pass through crevices/cracks/holes. The rock would crack, the disco ball could have each faces rigged by a mechanically engineered system that spaces them out.
4. both must be within a space containing "fine particles", i.e. a volumetric container, for the "light rays" to be "traced".

The "light rays" are shaped by the cavity of an obstructing solid element. A famous example in action movies:

Slightly related, on the Caustics page of the website, there is a demonstration of the Photon Tracing kernel featuring a disco ball (a sphere primitive geometry without surface smoothing) reflecting a spotlight ("concentric beam of light") with volumetric:



Somehow enabling volumetric on a sphere light won't result in that effect. It will rather look like a sphere light with the PostFX bloom enabled, no visible "light rays".

Volume rendering has become more sampling-manageable than it used to be thanks to all the optimization options and techniques available.