Decrease in lights power when using a lot of lights

[tomabobu]

Hello,

I've been experimenting lately with setups that use a lot of lights and I've found the following odd bug.
In the attached image the top section is rendered using one light and the one on the bottom uses that same light , in a cloner and duplicated 200 times (used this extreme number to show the problem).
The noise is normal since now it has to sample 200 lights instead of one, but the decrease in power and that weird shadow in the middle is not normal.
Can this be resolved somehow?

Best,
Bogdan

[aoktar]

Not a bug. Octane calculates the emission power differently indivual against collected meshes. Every week same question. To put a objecttag guarantees the same output.
Please see FAQ before posting: viewtopic.php?f=30&t=40997

[tomabobu]

There are two problems here :
1.The problem that worried me the most is the shadow that appears in the center of the light. What is that?

2.The second one is the dimming of the power with the number of lights
I've tried also with the object tag and I get the same problem : the decreasing power of the lights while increasing the number of lights.
See the attached image and scene. Render once with all the lights and then delete all but one and render again.

[aoktar]

What happens when you do same in Standalone? I suppose that you talk a general behaviour of emissions. Not directly related with plugins.

[tomabobu]

I don't think is a plugin related problem.
I never use Standalone in my projects as the plugin does everything I need and is a great experience.
I've made a quick test to export the scene to Standalone and it renders like in Cinema (bear in mind that my experience is limited in Standalone, I'm not familiar with the UI and the nodes so my test was just to open the scene and render it)

[uncia]

I don't think is a plugin related problem.
I never use Standalone in my projects as the plugin does everything I need and is a great experience.
I've made a quick test to export the scene to Standalone and it renders like in Cinema (bear in mind that my experience is limited in Standalone, I'm not familiar with the UI and the nodes so my test was just to open the scene and render it)

Hi. Just don't touch "Opacity" slider Set it back to 1
And in "Visibility" tab Uncheck "Camera visibility" and "Shadow visibility"

centerShadow1.zip

(89.48 KiB) Downloaded 129 times

[uncia]

Hello,

I've been experimenting lately with setups that use a lot of lights and I've found the following odd bug.
In the attached image the top section is rendered using one light and the one on the bottom uses that same light , in a cloner and duplicated 200 times (used this extreme number to show the problem).
The noise is normal since now it has to sample 200 lights instead of one, but the decrease in power and that weird shadow in the middle is not normal.
Can this be resolved somehow?

Best,
Bogdan

And about "the decrease in power" - it's because of GI_Clamp value . If it's set to "1" then you will have dimmer lights

[tomabobu]

Thanks Uncia for your help. It's great to have a solution for this.

Is there a situation when the "Opacity" slider is usefull? Or it shouldn't be touched ever.

Also the problem still exists if you use "Direct Lighting" with a any of the methods other than GI_DIFFUSE.
The center of the lights darkens and the light power dims with the increase in the number of lights.
Is there a workaround for this situation?

Thanks again,