Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: flood on 2018-04-01, 18:58:53

Title: Disable shadows of a Light
Post by: flood on 2018-04-01, 18:58:53
I want to disable the shadows of certain lights. I don't want to disable the shadows of an object. I just want to have the choice in Corona which light produces shadows and which don't.

So the object will receive shadows from light A but not from light B.

For example:
I'm working on a scene where I like how the front light hits the tree but I don't like the shadow that is beeing cast towards the back. I do like the shadow that another light (shining from behind the tree) produces. It's a nice soft shadow that is projected toward the front.

Is there a way to get this kind of result?
(http://scene001.png)


Title: Re: Disable shadows of a Light
Post by: mferster on 2018-04-02, 19:04:12
You can only do this if you are using a shadowcatcher material and enabling the shadowcatcher illuminator setting in your lights... However, by looking at your image I don't think that would be suitable.
Title: Re: Disable shadows of a Light
Post by: TomG on 2018-04-02, 19:21:54
There's no way to define that a particular object only casts shadows from particular lights. However from what you describe, you could use a 3ds Max native light with Shadows disabled (so long as it wasn't required that it cast shadows for ANY object in the scene... if you just wanted it to cast no shadows from the tree, but cast shadows from everything else, then that would not work).
Title: Re: Disable shadows of a Light
Post by: flood on 2018-04-02, 20:03:51
Thanks for the reply's.
At the moment i'm using the standard 3ds max light as TomG suggested to turn off the cast shadows of that light but it i'm not getting the results that I want. I'm getting other kinds of "problems" too where I really need to tweak the render but no tools are available.

This is the first time i'm using Corona, I have invested in a license since MentalRay was discontinued but i'm really having a hard time setting up the renderer how I want to. I was really into mentalray but I have to move forward...

So i'm starting to wonder if i made the right renderer choice for the projects that i'm planning to use it for. Currently working on a childrensbook, so i'm not really using corona for realistic renderings.

The way things are going now is that i will have to render a lot more in pieces in get everything together in post-production if I stay with Corona, or I could end up looking at other renderers.

Spend I whole day today attempting to "master" Corona but have gotten nowhere.


Title: Re: Disable shadows of a Light
Post by: Lucutus on 2018-04-03, 08:19:55
I came from Metal ray too, and fpr me it was pretty easy to get into Corona.

The toon style u are trying to archieve is something special of course.

First of all...from one Mental Ray user to another....usually u can stay away from the render settings in Corona.
Just care about your resolution and your noise level. Maybe about your secondary solver...but in most of the cases thats it.
I would suggest that u touch the other settings only if you really know what you are doing.

In the most cases the "problem" can be solved within the materials or the lights.

according to your special light issue. I would also suggest to use one or maybe several standart lights with shadow turned off.
Maybe you can also try to specify the distance falloff in a way that it matches your needs.

U wrote that using the standart lights you are facing other "problems". can u be a bit more specific....maybe its easier to solve these too.

greetz

Lucutus
Title: Re: Disable shadows of a Light
Post by: PROH on 2018-04-03, 10:01:23
Hi. I'm also an old mr user, and one of the things I found most difficult (but also most pleasant) when changing to Corona, was not to do things the "complicated" way I was used to! Corona is actually straight forward :)

As Lucutus said, leave the render settings at default (exept the choice of secondary solver) and work with materials and light instead.

The only thing I really miss, is the way mr worked with the standard Ink&Paint material. Hopefully there will be some sort of ink/toon shader in Corona at some time (not too far away).

Regards
Title: Re: Disable shadows of a Light
Post by: flood on 2018-04-03, 12:34:03
Well, i have made use of the advice you all gave me and i'm starting to see improvements in my renderings.

At the moment, for the current scene i'm working on I have deleted the entire light-setup and started fresh. I now use CoronaSun (makes more sense because it's an outdoor scene) and one normal spotlight (without shadows on) to kinda get the hardness out of the shadows of the sun.

I tried not to change corona settings but always lighting and textures. The sun at 1.0 is too strong in my scene, I had to get it down to 0.5 and change the camera ISO to 200 to get a normal lighting. It is starting to look good so thank you for all the advice.

Corona does crash a lot (almost every time) when using interactive rendering and then trying to change the camera settings (use photographic(ISO) settings). I have to turn off interactive rendering, change the setting and then turn back on interactive rendering.
Title: Re: Disable shadows of a Light
Post by: TomG on 2018-04-03, 13:38:55
Are you using a Corona Camera? That would be the best way to control exposure settings, and should not crash (if it does, please post a bug report about it!)
Title: Re: Disable shadows of a Light
Post by: romullus on 2018-04-03, 13:51:40
[..] to kinda get the hardness out of the shadows of the sun.

If you want softer shadows from the sun, you can increase sun size in command panel.

Corona does crash a lot (almost every time) when using interactive rendering and then trying to change the camera settings (use photographic(ISO) settings). I have to turn off interactive rendering, change the setting and then turn back on interactive rendering.

Crashing is not normal, please report it as a bug (https://coronarenderer.freshdesk.com/support/solutions/articles/5000524006-how-to-report-issues-3ds-max) or open support ticket (https://coronarenderer.freshdesk.com/support/tickets/new) and the team will look at it.