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I have come across this issue before in other projects, and I just move the light around, so I cannot see the reflection emitted from a light source. I have seen videos like this https://www.youtube.com/watch?v=9IjEXE70ujI go to time 1:25. But when I try it, nothing disappears. The only way I am able to get the reflection to disappear is if I uncheck transmission in the ray visibility section. But I have found that if I'm working with anything transparent, then the light doesn't go through the object anymore. As you can see the glass ball has light going through it landing on the P key, but I can see the light source in the reflection, and after I turn off transmission it will disappear, and you can see the window now but the hint of light that was passing through the glass also disappears.

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AlexWillis21
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1 Answers1

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A cheat:

Scene setup is a glass ball with Principled BSDF, Transmission of 1, an area light, and a primitive plane.

Here's rendered view:

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You can add a plane with a Transparent BSDF between the glass ball and the object to have light cast on it, in this case the floor.

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Then set your light to Use Nodes.

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In the shader graph we can specify that for a Transparent Depth less than one (.9 actually, non-inclusive?) we emit no light.

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Now we can see that the plane is giving us some problems, so we have to disable Camera ray visibility for the transparent plane.

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What this leaves us with is basically all of the light that goes through the plane, and it's taken the light source out of the glass.

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With a slight modification we can take out that giant white chunk at the top, and I believe we've mostly achieved the goal. You should have decent control over where the refracted light is allowed to show.

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To get the effect you want in your scene you might have to crank the wattage up. We're totally torturing this light, so any arguments about conservation of energy went out the window long ago anyway.

Allen Simpson
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  • All these little boxes, I think they are called nodes, what are they applied to. And if I did, that would the light source still be seen through the object if the ball is between the camera and the light. – AlexWillis21 Jul 06 '21 at 00:45
  • https://ibb.co/vqYvjv9 As you can see, I made the light circle, so it wouldn't blend in with the reflection of the window in the background. But that gave me an idea, so I just made multiple lights and made them the same size as each window lowered the emission and used an area light to control the spread of the shadow. So since I couldn't get the lights to disappear, the decoy lights covered for the circle light that I was trying to hide. https://ibb.co/vXvVBQ4 – AlexWillis21 Jul 06 '21 at 00:45
  • The light itself, in the light properties there's a button to use nodes. – Allen Simpson Jul 06 '21 at 00:48
  • So are you saying I would have to place another transparent plane between the ball and the keyboard or the ball and the camera or the ball and the light? im confused what the orange lines are and the angle of everything im not sure where the extra transparent plane would go or the camera in respect to the model you set up – AlexWillis21 Jul 06 '21 at 00:48
  • alright, I can set it up like your scene, just discovered a small problem anyway – Allen Simpson Jul 06 '21 at 02:43
  • Wow ok that makes so much since. Thank you. So if the wattage is way up to get this effect then doesn't that mean everything else may appear over exposed. So just a side question. Can a light source only affect one object and ignore the other objects. For example a duplicated light in the same location, 1 cranked up wattage with these setting for the glass ball and the other like normal to light up the rest of the objects. – AlexWillis21 Jul 07 '21 at 03:40
  • Well the way we have it here is only the light that goes through the plane, everything else gets ignored assuming it doesn't have a Transparent shader, which I'm guessing nothing else in your scene does.

    What you might wanna do instead is look at this answer and set a different strength of the hdri for lighting than what is shown on camera - https://blender.stackexchange.com/a/134216/110840

     – Allen Simpson Jul 07 '21 at 04:00
  • Otherwise you might be in compositor territory, which would be better in a new question. :) – Allen Simpson Jul 07 '21 at 04:04
  • I didn't use an hdri. The window was an image on a plane. I just used planes with an emission to hide the area light. The planes were set real low so the area light would be the one that really projects the light – AlexWillis21 Jul 07 '21 at 12:51