Elevations and Terrain Types

Setting Elevations Using the Terrain Editor

Terrain elevations can be set in several ways – at just one vertex, over a large area of selected vertices, while assigning cell types, or by using the Filter. Elevations in the Aces High II Terrain Editor are measured in feet and are displayed as the Y coordinate in the Position area of the editor window.

To change the elevation of just one vertex, Left Click on the terrain to highlight a vertex, then set the elevation in Terr Alt and click the Set Terr Alt button. The elevation at that vertex will increase or decrease to the value shown in the Terr Alt box. If you use the Alt and Pitch sliders to adjust the view, you’ll notice that elevated the terrain at just one vertex makes an unnatural looking point.

Changing the elevation over a larger area works in much the same way as changing the elevation at just one vertex. Simply select an area of the terrain by Left Clicking, dragging, and unclicking, then set the elevation in Terr Alt and click the Set Terr Alt button.

Elevations can also be automatically set while assigning cell types/textures by checking the Auto Type checkbox. Select an area of terrain, select a type from the list, and click the Set Terr Alt button. The cell types will be assigned and set to the elevation that is shown in the Terr Alt box.

Terrain elevation can also be set in smaller increments, based on the value in the Inc Alt box. Select a single vertex or an area of vertices, then click either the Raise button or the Lower button to raise or lower the terrain. Repeatedly click these buttons to incrementally increase or decrease the elevation of the selected vertex or vertices.

The Filter is used for constructing natural looking hills and valleys over large areas.

Using Setup Filter

To get started with the filter click the Setup Filter button to bring up the Filter dialog window.

The first thing you should notice are the three control groupings labeled “Sin Wave”, “Saw Tooth”, and “Square Wave”. These are the three waveforms that you can apply to the terrain surface. They will alter the terrain similar to:

Each of the waveforms has several common variables. “Alt Feet” is essentially the amplitude of the wave to be applied to the terrain. The waveform can be applied along one or two axis. However, the wave along each axis can have its own wavelength (i.e. the distance between two consecutive wave peaks). These are labeled “X Miles” for the wavelength along the X-axis, and “Y Miles” for the Y wavelength along the Y-axis. To apply a given wave form along a given axis, check the “X” or “Y” axis checkbox and enter a wavelength.

Multiple waveforms may be combined together for interesting effects. For instance, you may combine a Sin Wave along the X-axis, with a Square Wave along the X and Y-axis, entering different wavelengths for each axis. Normally, however, you will be using the Sin Wave (on BOTH the X and Y-axis) to produce natural looking undulating hills. TIP: Applying the filters to only one axis will result in a terrain almost exactly like the pictures of the wave forms shown above.

Near the bottom of the dialog you will see controls for transitions. These options allow you to establish a specified boundary around the applied waveform to be blended into the surrounding terrain. The “Enable Transition” checkbox must be checked for this effect to be applied. Normally, this will be advisable to create a natural looking terrain and to avoid abrupt changes in the terrain surface. The number of vertices will define how wide the transition boundary will blend out past the area that the waveform was applied to. Checking the Show Transitions checkbox on the terrain tool will show transition vertices in white on the terrain. TIP: Be sure to assign enough vertices to the trasitions, and apply them to the top, left, right and bottom to avoid a steep cliff on the terrain. That is unless you want a steep cliff somewhere.

In addition to the width of the blending boundary, the direction of blending may also be constrained. The top, bottom, left, right checkboxes, when checked, determine which sides of the selected area the blending is applied to. If any of the checkboxes are not checked, that side of the selected area will exhibit an abrupt transition between the modified and surrounding terrain.

Once the Filter is set up and an area of vertices has been selected, pressing the “Perform Op” button will apply the waveforms defined in the Filter dialog to the selection. Take some time to try different wave combinations and transitions to experiment with different terrain effects. TIP: The larger the area you select for the filter, the more natural the hills look.

Example of Sine Wave results:

Using Grayscale Elevations

As you may have guessed by now, setting the elevations on even a small terrain would be a tedious job to say the least. Thankfully, the Terrain Editor allows you to import the elevations from a grayscale bitmap.

Some things to keep in mind while creating a grayscale elevation bitmap are:

• Grayscale 0 equals 0 elevation(terrain altitude) in the Terrain Editor
• Grayscale 255 equals the maximum elevation(terrain altitude) on your terrain
• The grayscale image must be a grayscale(not color) 8-bit BMP image.
• ALL grayscale elevation BMPs are 1024 x 1024 in size.
  • A grayscale elevation that uses the full 1024 x 1024 size of the image would be a 512 mile terrain.
  • A grayscale elevation that uses the center 512 x 512 of the 1024 x 1024 size of the image would be a 256 mile terrain.
  • A grayscale elevation that uses the center 256 x 256 of the 1024 x 1024 size of the image would be a 128 mile terrain.
  • A grayscale elevation that uses the center 128 x 128 of the 1024 x 1024 size of the image would be a 64 mile terrain.
    • The unused outer portion of the image should be filled with grayscale 0

There are many ways to create your elevations, including hand drawn in any graphics editor, using satellite imagery and using either commercial or freeware terrain generators such as Terragen, World Machine or Grome. You can also combine these for some interesting terrain effects.

Using these external programs is beyond the scope of this document. Information on how to use these programs may be able to be found in the Tutorials section of Content Creation.

Importing a grayscale bitmap is quite easy. To import a bitmap, click File->Import. Select the bitmap you wish to import, set the maximum elevation for your terrain, and click Ok.

Example of a grayscale elevation file for a 256 mile terrain (example is in jpg format to conserve size):

Grayscale Elevation File

Setting the Terrain Type

Setting the terrain type does several functions all at one time.

1. It sets the texture displayed on the terrain
2. It sets the clutter tile types used on that area of the terrain
3. It sets the characteristics of how a vehicle travels over the terrain (amount of bounce)

Setting Individual and Multiple Cells

To set the type of terrain, either left click in the center a single 1 mile grid or over a larger area by Left Clicking, dragging, and unclicking. Then select the terrain type by selecting the type from the list in the terrain tab and click the set Set Type button.

When you set the terrain type, the Terrain Editor initially sets the sub types for that area so they are all the same type. This makes it appear that the 1 mile grid is a single texture. In reality it is comprised of 4 one half square mile textures(sub types) described below.

Sub Types

There are four sub-types for each type of terrain. These are variations of the same theme with slight differences. This helps to prevent a "checkerboard" effect when flying over the terrain.

Each 1 square mile cell(grid) is divided into 4 equal sections called quadrants(quad).

You can manually adjust the sub-types for a single cell (1 mile grid) by selecting the cell and clicking the Manual button in the terrain tab. Then select which sub-type you want in each quadrant of the cell.

Randomizing Sub Types

Once you have set the general terrain types over your entire terrain, you can randomize the sub types over the entire terrain by clicking the Randomize button immediately after loading your terrain, and BEFORE clicking on a cell in the main editing window. You will be prompted with "Would you like to randomize the entire terrain?". Click Yes to perform the operation.

You can also randomize a single cell by selecting it and clicking the Randomize button.

Note on River Terrain Types

The river terrain types must be placed at 0 elevation on a terrain. This is because the terrain type contains water and water must be at 0 elevation.

If you place a river terrain type above 0 altitude, the river will not be able to be navigated by boats.

Limitations

• The maximum terrain elevation is 32,767 feet.
• Even though the grayscale import window says 64000 feet is the high limit, the limit is actually 32,767 feet.