Student: The parallel light problem

Started by noahding, October 29, 2021, 06:25:40 am

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noahding

Quote from: WAS on November 04, 2021, 06:38:25 pm
Quote from: Matt on November 04, 2021, 06:31:54 pm
Quote from: WAS on November 03, 2021, 01:38:43 pmIt would be nice to see improvements, as the sun technically is not a good choice at all, its a spot light essential, and is very noticeable as such when you use an object with its specular highlighting. This will even influence how the clouds receive direct light, especially with TGs issue with sun burning in clouds (creating giant hard glow circle that the first lighting setting can't spread out enough).

Noah's request was for parallel rays similar to those found in a parallel/infinite/distant light in other renderers. In Terragen the equivalent of this is the Sunlight node.

Yes, this produces a bright spot in the clouds in the direction the rays are coming from, but this can be turned off with "Glow in atmosphere and clouds" in the Sunlight parameters.

Quote from: undefinedWill soft shadows really somehow effect highlights?

Yes, the soft shadow radius will widen and soften out the bright spot in the clouds. (On surfaces the specular highlight doesn't quite work this way at the moment, but luckily we're talking about clouds here.)

Quote from: undefinedTo me it's very obviously like shining a flashlight with cascading rays. This will most certainly effect the Y+/Y- look like it does for any overcast scene looking at the sun area.

The self-shadowing rays will be softened by increasing soft shadow radius, as it simulates an area light.


Thanks for the explanation, and suggestions there with glow, I always thought that turned off highlighting in general so never bothered with stuff like thick clouds. All this information is handy.
Thank you very much for your answer ~ I have read your article (Cosmic Background (Stars and Galaxy) [2019 Night Sky]) this is a very wonderful Sky! I love it! Can this source file learn the following? Or where can I download and tutorial?

noahding

Quote from: Matt on November 04, 2021, 06:31:54 pm
Quote from: WAS on November 03, 2021, 01:38:43 pmIt would be nice to see improvements, as the sun technically is not a good choice at all, its a spot light essential, and is very noticeable as such when you use an object with its specular highlighting. This will even influence how the clouds receive direct light, especially with TGs issue with sun burning in clouds (creating giant hard glow circle that the first lighting setting can't spread out enough).

Noah's request was for parallel rays similar to those found in a parallel/infinite/distant light in other renderers. In Terragen the equivalent of this is the Sunlight node.

Yes, this produces a bright spot in the clouds in the direction the rays are coming from, but this can be turned off with "Glow in atmosphere and clouds" in the Sunlight parameters.

Quote from: undefinedWill soft shadows really somehow effect highlights?

Yes, the soft shadow radius will widen and soften out the bright spot in the clouds. (On surfaces the specular highlight doesn't quite work this way at the moment, but luckily we're talking about clouds here.)

Quote from: undefinedTo me it's very obviously like shining a flashlight with cascading rays. This will most certainly effect the Y+/Y- look like it does for any overcast scene looking at the sun area.

The self-shadowing rays will be softened by increasing soft shadow radius, as it simulates an area light.

Okay, but if it's -y and the sun is at -90 degrees below the horizon, the clouds will look wrong. I think it is possible if horizon occlusion can be eliminated, but I can't find how to eliminate it

WAS

Quote from: noahding on November 05, 2021, 04:54:59 am
Quote from: Matt on November 04, 2021, 06:31:54 pm
Quote from: WAS on November 03, 2021, 01:38:43 pmIt would be nice to see improvements, as the sun technically is not a good choice at all, its a spot light essential, and is very noticeable as such when you use an object with its specular highlighting. This will even influence how the clouds receive direct light, especially with TGs issue with sun burning in clouds (creating giant hard glow circle that the first lighting setting can't spread out enough).

Noah's request was for parallel rays similar to those found in a parallel/infinite/distant light in other renderers. In Terragen the equivalent of this is the Sunlight node.

Yes, this produces a bright spot in the clouds in the direction the rays are coming from, but this can be turned off with "Glow in atmosphere and clouds" in the Sunlight parameters.

Quote from: undefinedWill soft shadows really somehow effect highlights?

Yes, the soft shadow radius will widen and soften out the bright spot in the clouds. (On surfaces the specular highlight doesn't quite work this way at the moment, but luckily we're talking about clouds here.)

Quote from: undefinedTo me it's very obviously like shining a flashlight with cascading rays. This will most certainly effect the Y+/Y- look like it does for any overcast scene looking at the sun area.

The self-shadowing rays will be softened by increasing soft shadow radius, as it simulates an area light.

Okay, but if it's -y and the sun is at -90 degrees below the horizon, the clouds will look wrong. I think it is possible if horizon occlusion can be eliminated, but I can't find how to eliminate it

From what Matt said, you should be able to uncheck the "glow in atmosphere and clouds" box in the sun shaders. May also need to adjust soft shadow diameter in the the sun's as well.

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