Skies without the Truman Effect- Part 2

by Malefico

In Part I of this boring tutorial, we've seen a brief introduction to some of the possibilities Worlds in Blender can offer to us. This time, we'll see some others like animating the sky to make a storm approach threatening or whatever you imagine to do.

In the beginning, it was dark...

What follows probably only make sense to Linux users. I guess Windows` users will have it easier but honestly I don't really know. If this is your case, please just ignore this paragraph and move onto the next one. Seeya.

We are going to start in a new way: BY NOT STARTING BLENDER.

Instead we're going to compile some plugins sources Blender for Linux is packed with (at least in the static version). The sources can be found in the subfolder plugins/texture within the Blender directory (eg: /usr/local/blender/plugins/texture).

If you go there, you'll see a couple of files with the extention .C. We'll move to the higher folder (let's say "plugins") where we can find a nice Makefile.Go ahead, type "make" press ENTER and see what happens. We have just compiled the "tiles" and "clouds2" plugins, plus some other stuff we're not going to use right now. The important files are called "tiles.so" and "clouds2.so".

The Clouds2 plugin will be very useful since it offers many enhances from the original Clouds texture generator.

NOW, let's start BLENDER...

Then, the Cloud was created

Linux and Windows users will get together now for the rest of this tutorial.
Now that we are peacefully staring at the familiar Blender screen, let's create a simple scene for our experiments. It could be... a cube over a plane. Or if you feel rather original, 2 cubes over a plane. Whatever. It's your choice.

If you have already read the first part, you will surely know how to create a World for our scene. But if you haven't... read it now !.

Our scene will probably look like this:

We are going to create a world by left-clicking on the World button.

Now we'll click on the button with the little white square, and then ADD NEW.

We are going to create some stunning clouds for our world. Let's click on the TEXTURE button, choose PLUGIN.
Click on LOAD PLUGIN and the 3D window willl change into a folder tree. Surf it till the place where the plugins are located. Select the file "clouds2.so" (Windows users should select "clouds2.dll").

If everything went right, we should be able to see the plugin options in the texture panel.

Play with the parameters to get a couple of good looking clouds, but keep in mind not to waste too much time in this step because everything will change suddenly in a minute.

In my opinion, the clouds we can get thru this plugin are very superior from the ones we can get thru the original Clouds filter.
We can obtain cloudy stormy skies as well as naif white-and-blue ones. Anyway, patience is required to get good results.

You can copy the parameters in the screenshot to get some cheap and goodlooking clouds.

If you don't have this plugin, get it. But if you can't, don't despair. The original Clouds filter will do it well for the rest of the tutorial.

Si per si muove (However, it moves)

Go back to World. The left part of the world control panel was more or less explained in the first part of this tutorial, so we are not going to worry about them. To get some "Magritte" clouds just copy the values.

We are going to focus on the right part of the panel:

The VAR control changes the ammount of blending between the texture and the colours set by the HORGB and ZERGB controls in the left part of the screen. This way we can make our clouds look like vannishing or at the contrary make them stronger.
All geometric aspects can be adjusted with the SizeX, SizeY, SizeZ, dX, dY and dZ controls.

The COL control changes the ammount of blending between the texture original colour and those of the world (colour channel) while the NOR control changes the 3D aspect of the texture (changing the module of the texture's normal vector).

HORI and BLEND tells Blender to apply a colour to the horizon (RGB) and to blend the textures with the sky colour.

But the most funny and interesting FX we'll see, will show up by pressing the "OBJECT" button in the middle part of the world panel.

Now and without further explanations (bwehehehey) go back to the 3D window and press the SPACEBAR and ADD->EMPTY.

We have just created an "empty" which in other words is nothing at all. An empty is just a 3D point that allow us to control almost any NON-3D object. In this case, it will allow us to control the sky movement as if it was a "sky handle".

To our macchiavelic goals, we'll call it "Sky" ("Cielo" in spannish) and we'll rotate it (if necessary) so the Z component gets perpendicular to the floor plane.

Once we have done this we will connect our world with the empty. To do this, go to the World options and click in the button shown in the image. Once here, type in the name of the empty (in our case "Sky", in the image "Cielo").

Now, any movement assigned to the empty will effect in the cloud texture of the World.adding motion to the clouds or whatever texture was assigned to the empty.

One annoying thing that can happen is that when we activate the "OBJECT" option the world's representation to the left of the screen changes suddenly. That's why I told you not to waste to much time with it.

And worst odf all is that right now, the representation has little in common with what you achieve at rendering the scene (F12). Colours will remain untouched but texture's orientation will probably be shift in any direction. To fix this, all you have todo is move a little the empty, rotating or displacing it a litte should do it well. To check quickly your results, hit F12 every now and then.

Let's continue. Select the empty and be sure of being at frame 1 (press SHIFT + LEFT CURSOR key). We are going to insert a location keyframe. Press "I" with the empty selected and choose "Loc".

Now let's move to frame 20 and move the empty towards any direction but not too far.

Insert a new Loc keyframe. Well done, that all.

To try if everything went right, go back to frame 1 and press ALT+A, you should see the empty moving between the two locations you inserted keyframes in. However, if we render the animation as it is, we'll probably get a rather dissapointing result. Most probably we'll see a too fast movemente of the sky, something like a sky "blinking". Now it's time to edit the IPO curves. For whatever that means.

Now, the details

To fix the empty's animation curves, select the empty and press SHIFT + F6 (yes, the IPO curve), the 3D window will change to an IPO window, where three curves should be drawn. Each one of these curves represents the change in the three coordinates between the Loc keyframes.

The shape of these curves will vary depending on the movement we have assigned to the empty. If we have moved the empty only over one axis, we should see two horizontal straight lines meaning constant values for the other two axis, and one smooth curve representing the change in that coordinate.

In the IPO window curves are selected in the same way objects are in the 3D window, and are edited the same way too (TAB).

We have to flat down the curve so the animation get slower and smooth.

Select any curve and TAB into Edition Mode. Now press A key to deselect all nodes. Select the rightmost node, grab it (G) and move it so the curve becomes almost flat:

Once you have edited all curves (if needed), try to render the animation. You'll see that the sky moves much slowly and softer, creating the illusion of the natural movemente of the clouds in the sky. Moreover, the clouds will change in front of your eyes as if in the real world !.

You can download a small sample of what can be done from here.

What if the wheater get worse ?

Before finishing up this cloud stuff, let's see briefly some interesting FX we can make with World IPO curves.

We are going to ruin our peaceful blue sky changing the ZenRGB colours as seen in the image below:

Practically every World option can be animated by the animation menu which can be accesed thru the "I" key as we did before in the camera tutorial.

If you don't believe me, try it by yourself. Move to a middle frame in your animation and locate the mouse over the World panel. Press the I key. A menu like this should pop up:

Choose ZenRGB. Now move 5 or 6 frames ahead and change the ZenRGB values to the ones shown in the figure. This should look pretty similar to the colours of the sky in the very moment of a lightning taking place.

Call the animation menu with I key, and select ZenRGB again. From this frame on, the sky will change to the new colour, but since we want it to change briefily , we will edit the IPO curve...

As usual, move the mouse over the 3D window and press SHIFT + F6. Our already known IPO window will show up. Click on the small button with the World icon on it, over the lower part of the IPO window. Three new IPO curves will be seen. These curves represent the colour components of ZenRGB (namely the red, green and blue component).

Select any curve, TAB into Edition Mode and add a node to the right of the rightmost node. To add a node, keep pressed CTRL while left clicking on the place you want the node to be. Now move the node up or down to the level previous to the first node. By doing this we are returning the olour component to the value previous tho the keyframe. Do alike with the other curves till we have three "peaks" instead of three "steps".

Test render the scene and fix the curves as needed to achieve a convincent lightning colour. A small sample of my lightning can be downloaded from here.

Well, that's all for today, I hope the explanation was clear enough and useful for all of you. Now, it's time to get some sleep....zzzzz