Environmental Settings Dialog Controlling global lighting and other environment effects

Environment Settings

To access this dialog:

• Double click any empty space in the active 3D window.

• Activate the Format ribbon and select 3D Display | Environment

The Environmental Settings dialog is used to control the global parameters for lighting (directional and ambient), fog and sky, clipping and view exaggeration in the active 3D window.

The settings described here apply to the currently active 3D window and all linked external windows. Independent windows will be unaffected.

 

Field Details:

Ambient Light:

Active : select the check box to apply ambient light.

Intensity : move the slider bar left to decrease, or right  to increase the light intensity.

Ambient light is the background light that illuminates all3Dobjects from all directions simultaneously. For example, with ambient lighting, a scene may look like the following: However, with the ambient lighting turned off (and the directional light's latitude and  intensity increased) the following effect is achieved:

 

Directional Light:

Active : select the check box to apply directional light.

Intensity : move the slider bar left to decrease, or right to increase the light intensity.

Directional light is focused light that illuminates surfaces that are angled towards the light source.

 

Azimuth: this dial is used to specify the left-right azimuth location of the global light source for your scene.

Latitude: this dial is used to specify the up-down latitude of the light source. The center line of the dial can be seen as the 'horizon' of the view plane in this instance.

Headlight: select this option to apply a more focused, directional light projection; by default a global light is applied. The images shown below, a global light is shown on the left, whereas the right image shows the Headlight option enabled and applied:

2 Sided: select this option to illuminate surfaces from both sides. With this option not selected (default) the brightness of a surface will depend on the direction of the surface normal, regardless which side of the surface is being viewed. For a correctly-verified DTM, being lit from above, with the 2 Sided lighting option disabled, the underneath side of the surface looks dark (in shadow), whereas with this option enabled, the surface looks bright from above and below.
 

This option can be used to avoid the patchwork appearance of wireframes with inconsistent normals, when viewed as flat-shaded wireframes.

 

Clipping: use these controls to 'clip' the data in the display area. This allows you to restrict virtual data display to a specific 'corridor' of information. You can set the width of this viewable area using the following controls:

Front: set the minimum distance from the viewpoint that you wish to view data. A value of [1] indicates that data will be shown from the specified point 'backwards' into the virtual scene. Setting a higher value set the clipping position further away from the viewpoint. For example, if the following image represented a Front clipping value of 2000 virtual meters:



...the following image could represent the same data set with a Front clipping value of 1500 meters:

Back: this clipping setting determines the cut-off point from which data is stripped from view. Using the example above, if the Front clipping value was set to [1500] (as in the image directly above), and the Back clipping value were set to [2000] meters, the following would be displayed:



Find out more about clipping in 3D ...

The clipping values specified are always set in relation to the viewpoint. If the viewpoint is moved (for example, as the result of a rotation or pan operation), the settings will be applied dynamically as the view is altered. The easiest way to visualize this is to image that the clipping limit values (Front and Back) are simply 'masks', attached to the virtual camera, that will affect whichever view of data is presented.

 

Bias additional clipping planes: use this option to move the clipping plane by a small amount to overcome visibility issues with data drawn on a section plane (default 0.01).

When usingSection clipping (front or back), numerical tolerance issues can cause data drawn exactly on the plane to be randomly clipped out. The clipping plane bias setting is used to allow the OpenGL clip plane to be shifted by a small amount to ensure that items on the plane get drawn. The actual value required will be a function of the view's front and back clipping plane distance and the scale of the data. A positive number here (0.01 by default) will push the OpenGL clipping plane backwards by the tolerance amount, i.e. not clip objects within the tolerance distance of the plane. Negative biases are allowed, and have the effect of ensuring items within the tolerance distanceareclipped out.

 

Use polygon offset: select this option to visually, slightly offset strings which have been digitized by snapping to a wireframe or section plane (default 'ticked'). Selecting this option will prevent the digitized data from being partially 'hidden' by the wireframe or section plane surface.

Background Color:select one of the following options and their associated parameters:

• Single: select this option to use a single background color.

Color: use the drop-down to select a standard or custom color.

• Gradient: select this option to use a gradient background color (default).

Top Color: use the drop-down to select a standard or custom color.

Bottom Color: use the drop-down to select a standard or custom color.

Top Color: use the drop-down to select a standard or custom color.

Bottom Color: use the drop-down to select a standard or custom color.

Fog:

The recommended settings for day-time worlds are Fog Color = Background Color = 'pale blue' Minimum = 1000 Maximum = 10000 This has the effect of "hazing" the horizon and blends the sky color into the sky texture. The distances used do however depend on the dimensions of your world. The units of distance will correspond to the units of distance used in your terrain surface i.e. '1000' corresponds to either '1000 feet' or '1000 meters' depending on the surfaces you have imported.

 

As a rule, the best effects are obtained by keeping the fog and sky colors the same. For mist or fog, use 'white', and for gloom use 'black'. Try matching the sky color to your sky texture to minimize edge effects. Fog varies linearly from the close distance to the far distance, for the best results it is recommended that you set the Minimum Distance very close (near to or at zero)) and gradually increase the Maximum Distance  until a satisfactory effect is found.  If the recommended fog, sky and lighting settings do not produce the desired effect, gradually decrease the Fog Minimum distance. If reducing the Fog Minimum distance has no effect, or if you suddenly lose all visibility, then the problem is likely to be with your graphics card or monitor. Check that your monitor is set to either High Color (16 bit) or True Color (32 bit) - lower color settings have insufficient color range to support these effects. Check that your card supports DirectX graphics, and download and install the latest graphics driver from the card manufacturer.

 

Active: tick the checkbox to apply a simulated fog effect to the VR view.

If the default color of the fog does not match the current sky color, you will be prompted with the following message: Selecting Yes will change the current fog color to match the sky color. Selecting No will apply the selected fog color. For example, the following scene... When fog is added, becomes:

 

1. • Color: using the drop-down, select the color of the fog. Again, if it is different from the current sky color, you will need to confirm this action.

   • From: this is the distance from your view position over which you have 100% visibility. The fog effect starts from this distance and then steadily increases.

   • To: this is the distance from your view position beyond which you have 0% visibility. The fog effect starts from the minimum distance until you have zero visibility at the maximum distance. This distance value represents the distance of the farthest object (from the viewpoint) that can be displayed.

Clouds: use these controls to select a background texture and associated settings:

Texture: if you wish to apply a texture to the sky, select the image path using the browse button, or enter the path to the image file directly into the text field.

1. • Tile size: set the maximum tile size for the texture. Your image will be tiled across the sky 'surface'.

   • Segments: specify the number of segments to subdivide the sky into.

   • Speed (dX): for animated image files, set the speed at which the texture image is translated across the sky surface in the X direction. The speed is measured in

   • Speed (dZ): as above, but represents the speed that an image map is translated in the Z direction.

View Exaggeration:

X : define an exaggeration factor for the X view axis (default 1, no exaggeration)

Y : define an exaggeration factor for the Y view axis (default 1, no exaggeration)

Z : define an exaggeration factor for the Z view axis (default 1, no exaggeration)

Exaggeration settings allow you to stretch the view of the data that is displayed (and not, importantly, the data itself). This function can be thought of as a 'view correction' that will allow you to stretch the data in any of the virtual axes in which a scene is rendered. Separate values are available for X, Y and Z values (remember that the axis in question is that which is represented by the scene as a whole, i.e. using a world coordinate system). This is a different behaviour to that described for clipping; rotating the data, for example, after exaggeration, will appear as if it is the data object that has been stretched - the exaggeration is not applied in relation to the camera. Exaggeration values are set as a factor (e.g. 1.0 = 100%).

 

Save As Default: store all current settings within the environment dialog as default settings for future use.

Apply: refresh the view using the current settings, without closing the dialog.

OK: save the settings, refresh the view using the current settings and then close the dialog.

Cancel: close the dialog without applying or saving the current settings.

 

	Related Topics
	Getting the right effect