Leveller tries to have an intuitive interface, so if you want to just dive in with the basics, this section is for you. Before going any further, you'll find it helpful to arrange this browser window so that you can read this text and also see the Leveller window.

You've probably got Leveller already started, and are looking at something like this:

This window is a view onto a Leveller document. You can have as many views as you want, but the rest of this manual will explain that. To get quickly started, do this:

Press the A key for a few seconds, and then the Z key. The grid in the left part of the window should slide back and forth underneath you.

With the NumLock key turned on, press the 4 and 6 keys on the numeric keypad, which should make the grid spin around. The 8 and 2 keys will make it pitch up and down, as if you were nodding your head. If you've played 3D video games, you'll immediately get the hang of this. The 1 and 3 keys slide you left and right, as if you were sidestepping, and the 7 and 9 keys roll your head around. Finally, the + and Enter keys on the numeric keypad move you up and down.

If you prefer the navigation keys to be elsewhere, they can be moved by choosing File, Preferences, Keyboard Controls... from the menu bar.

That's basically it for flying around. In Leveller, the grid (also called the terrain or the heightfield) stays put, and you fly around it to get the view you want. The Camera tool (the first one in the toolbar along the side of the window) does the same thing, except it uses the mouse.

You probably noticed that the funny line and dot in the right part of the window changed position as you flew around. This part of the window is an overview map that shows the heightfield looking straight down at it.

Since the heightfield is perfectly flat by default, the map is a single color because there is no relative difference in elevation values in the heightfield. To create some bumpy terrain, choose the Filter, gforge... command from the menu bar, and click OK when the dialog appears. Your Leveller window should now look something like this:

Now it's more obvious what the map is for. As you fly around, you'll see that the square dot on the map indicates your camera position, and the line indicates your line of sight. The length of the line grows shorter if you look up or down, so it also indicates your camera's pitch angle.

You can click and drag on the map to change the camera position and the line of sight. The left mouse button changes the position, and the right mouse button changes the line of sight. If you hold the Ctrl key down when clicking (and then let go after you start dragging), you can fly around the heightfield in a helicopter motion. The clicked point becomes the location that the camera moves around.

To change the way the heightfield appears in the 3D scene view, use the following commands:

• View, Rendition Style... (or Shift-F) to change the heightfield's default appearance. Note that the Draw the scene using the default drawing style option in the Document Preferences dialog should be checked on first, to make the default appearance be used whenever you stop flying.
   
• File, Preferences, Document Rendition Styles... (or Ctrl-F) to change the heightfield's appearance when flying and editing. Note that these settings only apply to the active document.
   
• File, Preferences, Application Preferences... (or Shift-Ctrl-F) to change the heightfield's appearance for all modes, whenever a new document is created. We recommend using this command immediately after installing Leveller so that your rendition preferences will be automatically chosen whenever you start Leveller.
   
• View, Raytrace... (or Alt-G) to perform high-quality rendering of the heightfield. This is not a rendition style, so the rendering only remains visible until you start navigating or modify the heightfield. If you are only changing the light position, or the heightfield's coloration, the scene will be quickly re-raytraced.
   

Of course, there's more to Leveller than just looking at a heightfield. The toolbars on the left side of the window (press Alt-9 to move them to the right side, if you wish) contain editing tools, which are described below:

	Camera	Positions and aims the scene's viewing camera.
	Light	Positions the light object. Mostly used when raytracing.
	Zoom	Magnifies/reduces the overview map.
	Pan	Pans/scrolls the overview map.
	Rectangular Select	Makes rectangular selections.
	Elliptical Select	Makes oval-shaped selections.
	Arbitrary Select	Makes irregular-shaped selections.
	Magic Wand	Selects areas of similar elevation.
	Text	Etches or raises text glyphs on the heightfield.
	Line	Places straight ridges onto heightfield.
	Rectangle	Places rectangular ridges/plateaus onto heightfield.
	Ellipse	Places round ridges/plateaus onto heightfield.
	Ramp	Used to create or add sloped formations.
	Dig	Used to lower part of the heightfield.
	Raise	Used to raise part of the heightfield.
	Flatten	Flattens parts of the heightfield.
	Smooth/Sharpen	Used to smooth/sharpen parts of the heightfield.
	Rubber Stamp	Used to duplicate parts of the heightfield.
	Crater	Makes a crater-type depression in the heightfield.

Choose the Raise tool by clicking its toolbar button. The tool panel at the top of the window will change to let you change settings related to the Raise tool, such as its strength and brush size. You can also pick a commonly-used brush size from the lower part of the toolbar (the buttons with the black circles on them).

Now move the mouse over the map so that the mouse pointer is near the line of sight. You should see a white dot on the camera view showing which part of the heightfield the mouse is over.

Click and drag with the mouse over the map. In the camera view, you should see the heightfield bending as you literally 'raise' it from the ground.

  Before

After  

To get the same coloration as shown above, choose the View, Colormap... command (or press F7), and choose the 'Earth and Water' colormap from the dialog.

When you're satisifed with your changes to the heightfield, press F3 or choose the Filter, Smooth command. Notice how the heightfield is smoothed to make your changes look more weathered. Other filters perform similar global effects. The commands below the separator line in the Filter menu are plug-ins, which are external code modules that can be removed, replaced, or added to, thereby enhancing Leveller's filtering capabilities. The same is true for data import/export features and raytracing shaders.

The tools all operate in a similar manner. Most of them have settings which can be accessed in the settings panel, and require clicking (and maybe also dragging) on the overview map. If you change the heightfield but don't like the result, choose the Edit, Undo command or press Ctrl-Z before doing anything else. The Filter menu contains commands to let you perform changes to the heightfield as a whole (or to the currently selected area).