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Participating Frequently
March 15, 2024
Question

Lighting Help, any way to tell an object to ignore physical lights?

  • March 15, 2024
  • 3 replies
  • 1225 views

Hi there, I'm pretty new at 3D Stager and I'm trying to essentially build a mockup for a glass product sitting against a very light gray background (I'm using the plane for this) casting a hard shadow on it using a spotlight physical light. Something like this photo below.

 

The problem that I am running into is with the physical light, the background color changes to white, and sort of makes it uneven like a gradient. I have been instructed to keep the background a specific flat solid light gray background so I'm wondering how I could achieve this without having to change the intensity of the lights or changing the material colors etc.

 

One way that "almost" works is using emission on the background and setting my desired color, however, that still won't get me a solid background as the physical light affects it.

 

So I'm wondering if there is any way to tell an object in this case the plane to ignore lights? so the light gray no longer turns into white? even if that was possible, would that mean the bottle no longer would cast a shadow on the plane? 

 

I thought about just rendering as PNG and doing the shadow in Photoshop, but the results in Stager are much more realistic.

 

I would appreciate any suggestions! 

Thank you!

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3 replies

JeanetteMathews
Adobe Employee
Adobe Employee
March 23, 2024

Hey hey!  Jeanette from the Stager team here.  So Stager doesn't yet have the capability to disable lights per object, but totally agree it would be useful and way easier in this case to get what you want.

 

Here's a work around I did:

 

Rotate your object so it's laying down on the ground and use the ground plane to catch the shadows instead of a plane object.  The ground plane is a special object that is basically a 'shadow/reflections' only catcher, so it won't have the fall off lighting effect.

 

Here's a screenshot I was able to achieve in about 10 minutes of fiddling.  Frosted vs transparent glass.

 

 

 

And a quick screenshot of the scene setup.  The bottle is laying straight down, and the camera is facing straight down at it for the render shot above.  If I had more time I'd play with the lighting to get a sharper shadow like the example you have above.  You want a very small emitter for the light source with less fall off than what I had, but maybe gets you started!

 

 

 

3DistAuthor
Participating Frequently
May 9, 2024

Hey Jeanette, I appreciate you spending time to figure this out for me. I apologize for the late reply.

 

Were you using the directional light in the example above? 

Ares Hovhannesyan
Community Expert
Community Expert
March 15, 2024

Can you share any sample image what you want to achive? That can help to understand your task more in details. Thanks

3DistAuthor
Participating Frequently
March 15, 2024

I did share a sample, does it not show up for you? I'll share here again. 

 

 

Ares Hovhannesyan
Community Expert
Community Expert
March 16, 2024

You can use only Spot lIght without Environment Light to achive such effect.  Please find final render and Scene capture. Hope this will help.

 

DavidLloydImageworks
Inspiring
March 15, 2024

This is an interesting problem and one that you would encounter if you were shooting this in the real world as well. I am not aware of any way in stager to tell an object to ignore lights. What I would do in this instance is to make your background plane white and rendering to a .psd. In photoshop I would create a layer underneath the rendered layer that is the exact color you need for the grey background.  Then set your glass object layer to multiply. in the layers panel you will find several hidden layers for "object selection" and "material selection". If needed, you can use these to select the glass object to clean up anything that might need to be separated from the background further. 

3DistAuthor
Participating Frequently
March 15, 2024

Hi David, This is a great solution! thank you.

 

I was hoping to avoid post-processing as I would be doing these for multiple renderings but that'll have to do for now.

DavidLloydImageworks
Inspiring
March 22, 2024

One more thing that donned on me randomly, if you lay the bottle on the ground plane without a plane underneath, it will render with a shadow and transparent background. Of course, you still need post in PS for the grey background, but it should cut out much of the work.