Author Topic: lighting without shadows casting  (Read 361 times)

2019-01-10, 21:59:29

Bormax

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Hello!
I need to light up some objects in my scene and do not light other objects. It's easy to do using include/exclude option in Corona lights. But problem in my case is that objects excluded from the lighting of Corona lights still cast shadows from these lights. Attached picture explains problem better than words. As you can see, sphere is excluded from lighting, but still cast shadows to the floor. Is it possible somehow to get rid off this shadow using Corona lights?
In Vray, for example, if the object excluded from illumination and shadow casting it doesn't cast shadow. Vray lights used in Corona give the same result as Corona lights - no lighting, but shadows are on picture. Mental ray's lights do the trick, but get a lot of noise to the picture, so it's not the solution.
Another option would be switch off shadow casting in object's properties or use CoronaRaySwitchMtl, but I need these object to cast shadows from other lights in my scene, so this is not the solution as well.
I would be grateful if you share your ideas how to solve this problem.

2019-01-10, 22:18:31
Reply #1

sprayer

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In sphere object properties unticking cast shadows will help?

2019-01-11, 03:03:06
Reply #2

Bormax

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Thanks sprayer. I though about this solution, but
Another option would be switch off shadow casting in object's properties or use CoronaRaySwitchMtl, but I need these object to cast shadows from other lights in my scene, so this is not the solution as well.
The was about properties and materials of the objects which cast shadows, in example scene it was that sphere

2019-01-11, 09:54:29
Reply #3

patrick.testa

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I remember that years ago I used a free plugin from Habware that lets you decide a light include/exclude list from the object and not from the light.
https://maxplugins.de/max2018.php?search=exclude&sort=Author
I haven't tested it with Corona but maybe it can help. (If it works and if you use online rendering like Rebusfarm, check if they have it installed before using it…)
Let me know if it works!

Patrick

2019-01-11, 19:06:57
Reply #4

Bormax

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Thanks Patrick! This plugin is for Max 2018, I have earlier version of Max, so I couldn't try it. But I suppose this plugin helps to organize exclude/include lists of lights. The problem in this case is different - objects block the light from the light sources even if they are in exclude list of those light sources.

2019-01-14, 10:45:26
Reply #5

patrick.testa

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Hi Bormax,
on Maxplugins.de you can find earlier versions too, but unfortunately I've tried to download the plugin and it doesn't work with Corona…
With scanline render it works and the desired objects can ignore individual lights and avoid casting their shadows but this is a very old plugin and doesn't even work with the photometric lights but only with the basic ones…
Sorry but I haven't other ideas… :(

2019-01-14, 11:46:21
Reply #6

dzintas

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You can try to use ray switch materials, leaving GI slot empty. Problem is that, way you won't get colour bleeding effect.

2019-01-14, 12:12:47
Reply #7

patrick.testa

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Also, working with the material, every light would be affected and you couldn't chose to include only specific lights…
Maybe in this specific case it would be easier to make multiple renders and work in post with masks to delete shadows?

2019-01-14, 22:03:21
Reply #8

Bormax

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You can try to use ray switch materials, leaving GI slot empty. Problem is that, way you won't get colour bleeding effect.

Thanks dzintas. I've tried this already, but unfortunately this it's not the way I need now
Another option would be switch off shadow casting in object's properties or use CoronaRaySwitchMtl, but I need these object to cast shadows from other lights in my scene, so this is not the solution as well.

2019-01-14, 22:16:34
Reply #9

Bormax

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Hi Bormax,
on Maxplugins.de you can find earlier versions too, but unfortunately I've tried to download the plugin and it doesn't work with Corona…
With scanline render it works and the desired objects can ignore individual lights and avoid casting their shadows but this is a very old plugin and doesn't even work with the photometric lights but only with the basic ones…
Sorry but I haven't other ideas… :(

Hi Patrick!
Thank you for your efforts to help!
Looks like I have to use Vray for this part of the project - it's lights can work separately with illumination and shadow casting. I think this will be more convenient for me in this case.

2019-01-18, 10:01:52
Reply #10

maru

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Short answer: this is currently not possible in Corona, as it does not accept some "fakes" like this.
Questions: What exactly is this needed for? Is this commonly used?

2019-01-18, 11:06:14
Reply #11

j_man

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Funny, I just posted a similar answer in a different thread but you could accomplish this by compositing two renders together.


J.

2019-01-18, 12:31:42
Reply #12

patrick.testa

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Short answer: this is currently not possible in Corona, as it does not accept some "fakes" like this.
Questions: What exactly is this needed for? Is this commonly used?
One use I can think of is to add some reflections or rim lights to improve the look of an object in scene, without having to pay attention to unwanted reflections or shadows on surrounding objects.
Although, I admit that I never needed it in my works because usually I have to make several different views of the same scene and I never have time to make separate light rigs for each camera, so I try to balance things for the best possible look with a single light setup…