Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] General Discussion => Topic started by: Otuama on 2023-01-23, 13:03:42

Title: Scaling Lights
Post by: Otuama on 2023-01-23, 13:03:42
Hi all.

A quick question about lights.

I never scale lights with the scale gizmo because I was told in the past that it can cause issues and artifacts.

I've just loaded a scene and someone has scaled rectangle lights & not used the width/height in the light settings.

Also other lights are scaled in the minus or look like they've been mirrored or something.

Am I right to think that it's bad practice to scale lights like that?

Thanks
Title: Re: Scaling Lights
Post by: TomG on 2023-01-23, 14:29:44
I've never had any trouble using the widget for scaling. I only use numeric input if I need precise sizes for some reason.
Title: Re: Scaling Lights
Post by: Otuama on 2023-01-23, 14:49:10
Hi, thanks for the reply.

Just to confirm, in your opinion it's ok to scale lights with the scale tool?

And the scaling being in the minus for example is ok too?

if that's the case then great

I was told wrongly years ago

(https://i.imgur.com/SivWYqK.png)
Title: Re: Scaling Lights
Post by: hurrycat on 2023-01-23, 15:17:43
I guess it wouldn't be too difficult for someone (with better Maxscript skills than me) to write a small script that translates scale sizes to light dimensions..
Having all those custom scales wouldn't sit too well with me, from a scene organization standpoint. For example, one could have two lights that are instanced, so same Intensity and Length/Width, but produce different illumination because of custom ScaleX/Y values.

Having said that, I too would like to know if it would be totally ok to scale lights and not worry about artifacts or other issues. Wouldn't you run into issues if you created a light of 1cm by 1cm with an Intensity of 1, and then scale it by a large value to have it illuminate a large scene?
Title: Re: Scaling Lights
Post by: Otuama on 2023-01-23, 16:17:54
The only reason I realised this was the case in my scene was because I selected all instances of the lights and there are some that have been scaled with the widget/gizmo.

So yes, I'd like to be sure because now I know it's like it in the scene I'm in it's winding me up.  Too late to fix now but before I made this post I told the person who did it not to in future.

Title: Re: Scaling Lights
Post by: TomG on 2023-01-23, 17:41:54
If you are using a Corona Light, it's intensity is actually "unit by surface area" anyway, thus the intensity changes according to the size of the light and there would be no artifacts.
Title: Re: Scaling Lights
Post by: maru on 2023-01-23, 18:07:18
After a quick check with the dev team:
- scaling may be an issue only in case of spherical lights (they will get worse shading = possibly more noise)
- with other shapes it should not make any difference whether they are scaled or not
Title: Re: Scaling Lights
Post by: Otuama on 2023-01-24, 21:21:15
Thanks all for the clarification and checking.