PART IV

Let’s spend a minute to understand what we put in here. What makes this picture so stunning?

A major factor in this scene is the altitude of the clouds. The effect with high altitude clouds is, that you‘ll be able to see a larger chunk of the sky. Thus, the sky tends to look more complex and varietyful. If you set the clouds high, they also look smaller ( a no-brainer, I know)  so you need to increase the maxium size of the clouds to the 2nd largest position in order to get the proportions right.

Now for the 3D settings. As you have read, the clouds are not very thick, the setting is at 8. Well, this raises the question, wether you should enable 3D-clouds anyway, since they eat up a lot of render time.

This picture is the same as above, but this time rendered with 3D-clouds unchecked.

As you can see, the clouds look less detailed and … more flat. So, if clouds play a central role in the composition of a scenery, you may want to leave the 3D checkbox on. This is not generally true, though. Some type of clouds cannot be done using the 3D version. It's only, that 2D clouds don't look right when they're supposed to be thick.

As for the clouds color, I’d like to encourage you to play with these settings yourself. Even if the only thing you’re after is realistic clouds, you will find many cloud colors produced by nature herself! May that be brown, yellow, red, gray, purple, golden etc…. There’s virtually any color possible, and so it is in Terragen. Force Majeur chose to have a gray color (with green increased a bit), which support the stormy scenery well (This picture won the “Storm” contest at Terracon).

The darkening (55%) and contrast (40) are just as a thick, rainy cloud should look like. If the same cloud wasn’t planned to be a dark rain cloud, a contrast setting of 20 would keep the dramatic touch while making the cloud look a little brighter.

Interesting is the persistence setting at 50. Don’t go far beyond that with low clouds, when 3D is set on, especially when using a small clouds size. This won’t look good and will “pixelate” your clouds like this (alt 64, thick 8, persistence 90):

In some cases, you would find persistence at 50 unnatural, but for high clouds, this interestingly gives more detail to the clouds, which in turn looks good. Try to increase the persistence when you have high clouds.

The atmosphere dialog is less important for the clouds, except for the decay. The decay filters the green and blue portion out of the white light, so that only red light remains, the more intense the decay takes effect (from your point of view, this is the case the closer you look down to the horizon). At the end of the day (also literally), red light colors white clouds red, which you need to consider when composing a picture.

Now let's look at the lighting conditions dialog. Of course, clouds cast shadows in ‘Force Majeure’. Without this option, we would barely have bright and dark areas in the picture, and therefore the picture would be less epic. To compensate for the large amount of shadows, and also to see some sunbeams in the haze, the sunlight strength was set to 650%.

As you can see, the “Effect of Atmosphere” parameter is left at its default value (100%). In this scenery, a higher setting wouldn’t have much effect, since we’re not looking towards the sun, plus there’s no landscape in front of which the atmosphere could glow. I’ve rendered this picture to show you the minor difference with “Effect of Atmosphere” set to 200% (you can hardly see any) :

The “Realistic sunlight penetration system” is checked, of course. This is what you should always do when setting the params for this dialog. I’m not gonna discuss this. But beside from making your scene more relalistic, it also has an effect on the clouds, since the more realistically colored atmosphere also impacts the color of the clouds and haze. You need to check this box, period.

Now, the background light tab is very important, as illustrated above, for your scenary. For this specificl image, we see the “shadow lightness” had been decreased significantly down to about 14. Now look at the color we specified for “Light from above” in the same tab, which is a dark green. We don’t see this color much in the clouds, but if you take a closer look, you can see the green. The low value for shadow lightness prevents this color from coming out more intense. Although mandatory for a high contrast scene, a low shadow lightness darkens any color, but the colors will still be there. Look at this, I put the shadow lightness value up a bit:

The other color setting support the greenish touch (of the clouds), by also having the green slider increased a bit (olive). But remember, just because of the low value for shadow lightness, you don’t see them instantaneously. Also, the colors are quite dark themselves.

The last tab to discuss is the “Lightning of atmosphere” tab. Both glow amount and glow power are cut down, to 56% and 14%. Why is this? Well, it’s always good to have a look. Look at this:

Do you see any defined cloud structure in the upper right part of the picture? There’s only a white glowing chunk, that’s it. I increased both values (glow amount and power) up to the default of 100%. The 650% of sunlight strenght overcast the clouds, so in order to make it look realistic, you need to cut down the glow values.

Now we’re done with the discussion of this stunning picture. It really deserves to be 1st place. Any component is composed extremly well. I hope this illustrates in what a complex way the various settings and parameters impact each other and vice versa.

BTW, there’s one more hint for you to consider, if you were about to try and create something similair: Make sure, your position is WITHIN the shadow. If it’s not, your sight will be overcasted by the glowing atmosphere and you will get mad, because there’s no way of getting good contrasts this way. And cutting down the sunlight strength won’t help much.