Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: marioteodoru on 2014-04-26, 04:18:53

Title: Help with daylight system
Post by: marioteodoru on 2014-04-26, 04:18:53
Hello,

i am trying to render a nigh time shoot, an outside scene in the desert.  I have about 4 square km area, which has track illuminated by light poles, and i want to get around 7-8 o'clock in the evening. But, with daylight system, and corona sun activated, no matter what hour or position i put the widget on, i get the same light intensity. Can anyone help me out with this? How do you set up a outdoor night scene?

Thank you.

Title: Re: Help with daylight system
Post by: maru on 2014-04-26, 09:50:02
I don't believe you. ;)

Doesn't sun intensity change even if you set your sun very close to horizon? Have you tried changing exposure value/highlight compression?
Title: Re: Help with daylight system
Post by: Ondra on 2014-04-26, 10:28:59
can you post the result you are getting?
Title: Re: Help with daylight system
Post by: marioteodoru on 2014-04-27, 01:10:02
Hello,

I tried again, it does change, but i was expecting pitch black at 23.00, using the same exposure. But the scene is still quite illuminated. Should i make a bigger groundplane? This one has 4 km. If i change the exposure down to -10 i get quite dark, but this will also affet other lights in the scene wich i need to stay bright.
I hope i make sense, please excuse me if i waste you time. I'm actually trying to get a nice sun set, just a hint, and use pole lights to illuminate the scene. Can you give me some tips? Should i make a earth sphere to get the right illumination ?


Thank you for you time.
Title: Re: Help with daylight system
Post by: marioteodoru on 2014-04-27, 02:51:57
As you can see, with daylight on (sunlight off) i have to underexpose a lot to darken the image even if it's 23.00. But then, the 400 floodlights of 500w each, just disappear (almost).

If i turn the daylight off, and remove the environment map, than the flood light appear, but i get the exposure to 0.

I have to mention that the 400 flood light are intersecting with geometry. But i never notice this to be a problem in other scenes. Also all geometry is DAE files exported from modo, and the original geometry is mostly triangle from step files. So it's quite a mess. But again, i never notice this to be a problem.

Title: Re: Help with daylight system
Post by: maru on 2014-04-27, 10:20:53
I'm not sure but I think Corona's daylight model does not support any hours after the sun goes below horizon. But I have two questions:
-why do you want sunlight at 23?
-why do you want to simulate skylight at 23? You could just use constant colour (you can find Kelvin temperature values for different parts of day/night in the web) or a nice night sky HDR.

In first post you stated you want to make it 7-8pm. Please post the images you get and what you consider wrong about them.
Title: Re: Help with daylight system
Post by: marioteodoru on 2014-04-27, 12:40:23
Hello,
thank you for your reply.

I am trying to get a sunset, in order to have just a bit of light on the area, and be able to use my flood lighst. Just like in real life, when the sun goes down and the stretlight come on.

I'am trying with an hdr now, i'll post as soon as i have something.