Render Controls

image of rendering control

Render Preview: Renders a low-resolution image based on all the current settings. This is invaluable when calculating when an image "looks right".

Camera Position/Target Position: The position of the camera and target in landscape units. The camera looks from the camera position in a straight line to the target position. X indicates horizontal position, Y indicates vertical position, and Z indicates height. The line in the small Terrain view shows the line of sight, although there is no indication as to which end represents the camera.
The "Fixed Height above Surface" controls mean that when moving the camera or target, the height is always a fixed amount above the terrain or water at that position. If the Z value is altered manually, the Height Above Surface value is altered accordingly.

Image Size: For unregistered users, image size is restricted to 1280x960. For registered users, the only limit is your computer's memory.
The 'Lock' checkbox in the Image Size window keeps the aspect ratio the same if you modify one of width or height.  Therefore, if this is ticked and you double the width, the height will also be doubled automatically.

Render Image: Renders the image at the specified resolution. Once you have finished rendering, a box appears telling you how long the render took, and the number of quadrilaterals drawn. The image is always rendered in TrueColour (24bits), regardless of your display mode.

Camera Properties

Camera/Target Position. Like on the Landscape Dialog, you can position the camera on the small version of the terrain. The exact x,y,z coordinates can also be entered manually. You can also position the target by editing the head, pitch (vertical angle) and bank (horizontal angle) parameters. The image shows the field of view of the camera.

Zoom/Exposure. Sets the values for Zoom level and Exposure factor (see Camera Settings, below). The zoom setting is shown visually via the angled lines on the terrain image.

Camera Settings

image of camera settings dialog

Photographic Medium. Here you can choose between Traditional Computer Graphics and Photochemical Film mode. The two Photochemical Film modes simulate the response of a proper camera, giving a result that looks more realistic.

Exposure/Light Sensitivity. When in Photochemical Film mode, this simulates the light response of a proper camera.  Corrected T-Stop is a modifier to the Exposure value, simulating the same setting on a traditional camera.

Zoom/Magnification. The Zoom emulates the zoom of a photographic camera (as in field of view), and does not just move the camera back and forward. Because Terragen does not emulate a "spherical" lens as in a photographic camera, lower zoom factors can appear very unrealistic, and it is inadvisable to set zoom too low.

To calculate field of view from Zoom, use the following equation:

FOV = 2*arctan(1/Zoom)

where Field Of View is in Radians (degrees = radians * 180 / Pi)

For photographers, there is a table of Field of View/Focal Length comparisons here.

The Orthographic mode positions the camera above the terrain with a 'flat' zoom setting.  This is used for top-down renders, primarily for texture generation.

Effects. This allows you to select camera plugins.

Image Properties

Here you can preview the image to be rendered before you render it at full resolution and detail. Normally for previews, the middle detail setting is adequate.

The checkbox marked "Land" toggles whether the landscape should be rendered, and the checkbox marked "Sky" toggles the sky.

Render Settings

Atmospheric Accuracy. Sets the accuracy for the atmosphere. Normally the middle setting provides an image of good quality and only occasionally should you need to increase these values. Accuracy settings have a considerable impact on rendering times. In many cases, settings even lower than middle can produce very good results with lower rendering time.

Cloud Shading. Sets the accuracy for cloud shading. This does not have much effect with 2D clouds, but with 3D clouds an increase of this setting can yield dramatic improvements in image quality. However, the larger the value, the longer the rendering time.

Fast Sub-Pixel Smoothing. The default anti-aliasing method. Stops jagged lines at the edge of polygons.

Ultra. Provides extra detail at the expense of more memory and render time. This option is only available to registered users.

Extra Blended Detail.  Provides even more detail on the landscape - the sky rendering is not affected.

Render Landscape/Sky. The same as the checkboxes on the main render settings dialog. Once a cloud layer has been generated, you will almost always want to keep both checkboxes turned on, unless you are rendering a scene which does not include one or the other.

Back-face Culling. You should almost always leave this unless you deliberately wish to render the underside of the terrain. This disables rendering of polygons which are facing away from the camera (and therefore are invisible). This option can cut rendering time significantly.

Gamma Correction. Sets the Gamma Correction value for rendered images.  This value is not saved between sessions.

Memory Usage. This is used to limit the amount of memory used by Terragen while rendering images.  You should generally set this at 1/3 of your computer's available memory.



render controls

landscape

water

clouds

atmosphere

lighting

image
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©December, 2002 John McLusky