Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: John.McWaters on 2019-04-04, 16:36:31

Title: Best way to have HDR as background, but lighting from Corona Sun?
Post by: John.McWaters on 2019-04-04, 16:36:31
I would like to use the Corona Sun and Sky as primary lighting and GI (so I can have more control), but have the backdrop be an HDR. I want the HDR to act as background only, and all light to come from the Corona Sun and sky. What is the best way to go about doing this?

I was trying to use the Corona Ray Switching map and plugging that into the environment input, but I couldn't quite get it working correctly.
Title: Re: Best way to have HDR as background, but lighting from Corona Sun?
Post by: romullus on 2019-04-04, 16:40:21
There's enviroment overrides in render settings, that does exactly what you want. Activate direct visibility override and plug your HDRI map in its slot. That's it!
Title: Re: Best way to have HDR as background, but lighting from Corona Sun?
Post by: James Vella on 2019-04-04, 16:42:05
in render settings > scene > environment override > direct visible override put the hdri here

edit: beat me to it romullus :D
Title: Re: Best way to have HDR as background, but lighting from Corona Sun?
Post by: sprayer on 2019-04-04, 16:43:40
why do you need hdri if it's not light the scene? This is useless, you are wasting RAM, you need to plug image here
https://i.imgur.com/y7NlReG.jpg
also you may need to plug it first to corona tonemap node and untick options
Title: Re: Best way to have HDR as background, but lighting from Corona Sun?
Post by: John.McWaters on 2019-04-04, 16:44:43
why do you need hdri if it's not light the scene? This is useless, you are wasting RAM, you need to plug image here
https://i.imgur.com/y7NlReG.jpg
also you may need to plug it first to corona tonemap and untick options

I would like to have sky with clouds and subtle variations in tone.
Title: Re: Best way to have HDR as background, but lighting from Corona Sun?
Post by: sprayer on 2019-04-04, 16:49:37
Hdri store colors what you do not see on monitor. it is store sun light and it is for the light only, for background it is better to use ordinal image. also for spherical hdri for background if you plan to render big resolution image you need big resolution, hdri will be very huge just to load as background
Title: Re: Best way to have HDR as background, but lighting from Corona Sun?
Post by: romullus on 2019-04-04, 19:21:57
HDRI for background is not useless. It makes as much sense, as HDRI for lighting. In fact it's almost always preferable to use HDRI over LDRI  for background, if you have such luxury to choose.
Title: Re: Best way to have HDR as background, but lighting from Corona Sun?
Post by: sprayer on 2019-04-04, 19:29:40
romullus
for what purpose in case of this topic?  It will be not visible to reflection and not light the scene, but big hdri for light also not good imho. Good spherical hdri background 12k resolution will be 100mb+, it's wasting RAM what corona likes to eat =)
Title: Re: Best way to have HDR as background, but lighting from Corona Sun?
Post by: romullus on 2019-04-04, 19:37:53
Regular image has exposure locked in, which you must to match more or less closely in your scene, but with HDRI you have much more freedom to change exposure for your needs. As for RAM usage, same goes for all the assets in your scene - if you have enough RAM, you don't have to worry about a thing, but if you're thin on RAM, then you have to think about optimizations. For me it's almost always scenario No. 2 :]
Title: Re: Best way to have HDR as background, but lighting from Corona Sun?
Post by: sprayer on 2019-04-04, 20:01:54
but for background very often images looks likes reference and you need just match light setup for that and do not touch background. so i can't imagine scenario there you need to change exposure for background. also i am thinking 3ds max is not good for adjusting images, and corona color correction have many bugs then it working with HDRI (wrong saturation, and weird result with artifacts)
Title: Re: Best way to have HDR as background, but lighting from Corona Sun?
Post by: romullus on 2019-04-04, 21:01:42
I think you misunderstand me. What i want to say, that when you plug HDR image in the background, you then can freely change global exposure of the scene, making it darker or lighter and background will follow very naturally, unlike 8 bit image, which simply don't have enough information in the shadows and highlights for that.