The Lighting tab controls how objects are to be displayed in the 3D View.
| Item | Used to |
| Shading | Controls how DTMS are shaded in the 3D view. This can have the effect
of making the DTM appear as a smooth, curved surface. Flat shading means that this smoothing effect is turned off and each triangle in the DTM is coloured uniformly. Use this option with Sun Position "On" to view just Sun shading based on the Sun Azimuth and Elevation without the effect of Gourand or Phong shading. Gouraud shading means that this smoothing effect is on. There will be a computation of light at each vertex in the DTM and this gets interpolated across the triangle. This shading has performance advantages over Phong shading, but it has some shortcomings, where specular highlights may not be rendered accurately, and 'phantom' triangle artifacts can appear, where the underlying triangulation of the model can sometimes be noticed. Using this in conjunction with the Sun Position can lead to pleasing visual effects. Phong shading means that this smoothing effect is also on, but it uses a more complex algorithm to compute lighting on a per-pixel basis. This results in more accurate display of curved surfaces, and enhances the display of specular highlights. Phong shading, however, is computationally intensive and can lead to performance loss. Using this in conjunction with the Sun Position can lead to pleasing visual effects. |
| Sun Position | Controls where a light, to simulate the sun, is coming from. Use this
option in conjunction with "Flat" shading to view just the Sun shading based on the Sun Azimuth and Elevation
without the effect of Gourand or Phong shading. Check the On box to turn on. Azimuth refers to the sun's azimuth in the units configured in the database. Elevation refers to the sun's elevation in the units configured in the database. An elevation of zero means that the sun is on the horizon and is the minimum setting allowed, leading to the scene being darkly shaded. |
| Effects | Show Shadow will create a grey shadow of the scene below the
XY plane of the scene. This is to produce a visually pleasing effect. Show Fog will create a fog effect in the scene, such that things further away from the camera get progressively obscured. This is to produce a visually pleasing effect, and can also improve performance as not as many objects will need to be rendered. |