Author Topic: Making lights invisible in ground reflections?  (Read 1247 times)

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Offline archz2

Making lights invisible in ground reflections?
« on: February 03, 2022, 07:00:34 am »
I am trying to render a model wherein I need to have lights on but not reflected on the ground plane. I only want the base geometry to be seen in the ground reflection. How can I do it?



ksp file can be downloaded from here

https://we.tl/t-5p1cF4XWlu



Offline RRIS

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Re: Making lights invisible in ground reflections?
« Reply #1 on: February 03, 2022, 07:19:43 am »
If the lights are in the environment texture, then you probably can't. If the lights are physical lights (area lights), then you can disable them in reflections, but that might not get you the lighting you want on your object (as you will be missing the reflections  of the lights on that as well).

Offline mattjgerard

Re: Making lights invisible in ground reflections?
« Reply #2 on: February 03, 2022, 07:37:03 am »
RRIS is right, but the disable in reflections is only available in the Area Light light. They do look like HDRI pins.

As in all photography, its a balance between what we want, and what we can do. Need to play with light position, angle, camera position and angle. Also look into placing planes or objects in between the light and the reflective surface you want to block it from (we used to call these flags in the real world)

Until KS has the ability to do this on a per material basis, that's the only solutions that will work. Either that or some fancy photoshop work.

Offline archz2

Re: Making lights invisible in ground reflections?
« Reply #3 on: February 03, 2022, 07:56:44 am »
Also look into placing planes or objects in between the light and the reflective surface you want to block it from (we used to call these flags in the real world)


How do I hide the plane and still make it block light reflections?




Here is the updated ksp file.
https://we.tl/t-OMv72u2ji8
« Last Edit: February 03, 2022, 07:58:24 am by archz2 »

Offline mattjgerard

Re: Making lights invisible in ground reflections?
« Reply #4 on: February 03, 2022, 01:39:01 pm »
Also look into placing planes or objects in between the light and the reflective surface you want to block it from (we used to call these flags in the real world)


How do I hide the plane and still make it block light reflections?




Here is the updated ksp file.
https://we.tl/t-OMv72u2ji8

Make it an emissive object, turn it black and uncheck visible to camera and visible in reflections

« Last Edit: February 03, 2022, 01:41:12 pm by mattjgerard »

Offline archz2

Re: Making lights invisible in ground reflections?
« Reply #5 on: February 04, 2022, 01:47:57 am »
Still not working. This time Keyshot is not following basic laws of physics. How can an opaque black plane let a light pass through it?
I turned off 'visible to camera'. It's just for the screenshot purpose, I have toggled it on.


Here's the updated file.
https://we.tl/t-fpHyKJtCHm


Offline mattjgerard

Re: Making lights invisible in ground reflections?
« Reply #6 on: February 04, 2022, 08:16:55 am »
Here is what I came up with. I was mistaken you need to have "Visble in reflections" checked, otherwise the light travels through and is still visibile in the reflections. Move the flag around in this scene to see how it works. It will still be visible in the reflective floor due to this, but hopefully you can use position and camera angle to avoid it in the scene.

Offline archz2

Re: Making lights invisible in ground reflections?
« Reply #7 on: February 04, 2022, 09:01:52 am »
Yes. The situation is more or less the same.


If I turn off 'visible in reflections' then it allows light to pass through which shouldn't be the case.


Offline archz2

Re: Making lights invisible in ground reflections?
« Reply #8 on: February 10, 2022, 07:18:23 am »
Bump.........

Offline RRIS

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Re: Making lights invisible in ground reflections?
« Reply #9 on: February 17, 2022, 05:40:29 am »
Probably easiest to render it once without floor, with reflections turned on in your lights (to get reflections in your object). Then render again with the floor, but without the reflections turned on (to get the floor with the object reflections, but without the light reflections). Then composite the two.

Offline DT

Re: Making lights invisible in ground reflections?
« Reply #10 on: February 18, 2022, 03:12:35 pm »
Create a new model set with your model and apply the white emissive material to the model then turn off visible in camera and and shadows.
Then add a ground/plane to the new model set and assign a metal/mirror material.
Create a ground reflection mask studio and then add the new mask model set along with a black environment.
Once rendered you’ll have a mask of the reflection to remove the environment/lights from the ground reflection from the rendered beauty image.

« Last Edit: February 18, 2022, 03:17:13 pm by DT »