72. Open the TG Planimetric view.

73. Suppose you want to make changes to the terrain, but something more painterly and permanent than a Terraffector or Area Terraffector. That's where the new DEM Painter comes in. We could jump right to the DEM Painter window by selecting the DEM in the Database Editor and selecting Paint. Let's first look at the new DEM Editor by clicking the Edit button or double-clicking the terrain in the camera view.

74. This is the new DEM Editor. The Elevations page lists the elevation of all vertices in the DEM.

75. Zoom in a few notches with 3 taps of the + key and click on the cliff top left of the target.

76. The DEM Editor takes you right to the nearest terrain grid vertex.

77. Change the value here and at the surrounding 8 vertices to 75 meters.

78. Go to the File page and Save DEM to File.

79. Confirm that you understand the ramifications of your choice; there is no undo once you overwrite the DEM.

80. The realtime TG Camera view will refresh with your changes.

81. Return the camera to its default position and save the project.

82. Select DEM Painter and you'll see a grayscale plan view of the Groovy DEM.

83. Let's add some ridges to the mesa top. Select the Paint tool from the Tools palette.

84. Show Brushes and select the soft edged one at the bottom of the left column.

85. Show Options and reduce the Opacity to 50%. This is the strength of the paint effect, with 100% being full and 0% being none.

86. Show Elevations and increase the Foreground elevation to 100m. This is the maximum value of the paint effect.

87. Select the Preview checkbox to watch painting in realtime views.

88. Click and drag to raise terrain. If you make a mistake, use the Undo button. If you drag across a canyon, some of the underlying topography is preserved with the lower Opacity. Full Opacity would have raised everything under the brush to 100 meters.

89. You can also paint directly on a realtime view. The DEM Painter window may hide behind the DEM Editor. If you want to see it while you're painting, bring it forward with the Window menu item and move it to another matrix quad.

90. When you're done, Save the DEM to disk .

91. Once again, VNS will give you options for overwriting the existing DEM or creating a new one. Choose Overwrite.

92. Realtime views will reflect the painted changes.

93. If you're curious to see what the new terrain looks like, save the project and render a preview. This is a very simple application of the DEM Painter. Read more about in the Interactive Reference Manual and experiment on your own.

94. One of the reasons that VNS can render large terrain in a reasonable amount of time is that it renders the terrain surface differently than traditional 3D programs render 3D surfaces. To see this, we'll need to get a closer look at the terrain.

95. Open the TG Planimetric Camera View Preferences and change the view Width to 10 meters.

96. Render a preview. Here we see terrain polygons rendered at a Fractal Depth of 0, the default.

97. Bring the Database Editor forward and turn to the Extent page. Each Grid Cell is 3.3 meters on a side.

98. At a Fractal Depth of 0, each grid cell is rendered as 2 polygons, which we can see clearly in the preview render.

99. Open the Terrain Parameter Editor and increase the Maximum Fractal Depth to 1.

100. Close out the DEM Painter and DEM Editor. Open another TG Planimetric camera view in the upper left quad.

101. Render a preview.

102. With each increase in Fractal Depth value, each polygon is further divided into 4 polygons.

103. Vertices shift vertically according to the Vertical Displacement percentage and horizontally if Horizontal Displacement is checked. Increase the Maximum Fractal Depth to 7, the highest value.

104. Render a preview.

105. Each original polygon in the right camera view has now been rendered as more than 16,000 polygons, each only a few centimeters on a side. The increase in apparent detail is significant. The key word here is apparent. We have not increased actual terrain detail. The original grid polygon edges are still there, we've just made them less obvious.

106. Now that we know what Fractal Depth is, let's talk about the 3 ways of rendering it. In the Terrain Parameter Editor, the default Fractal Depth method is Variable. This renders near polygons at a higher Fractal Depth, where we can see them, and decreases Fractal Depth with distance. Variable Fractal Depth is a good choice for still images. Constant Fractal Depth renders the same Fractal Depth everywhere, which will significantly increase render time. Fractal Maps are Variable Fractal Depth for animations. When Fractal Depth Maps are created, VNS maps near and far polygons along active camera paths.

107. While we're talking about terrain detail, let's look at bump mapping. Bump mapping can be applied to the terrain via a Ground Effect. It can increase the realism of the terrain surface while hiding unsightly polygons.

108. Go to the Land Cover Task Mode and open the Ground Editor to the Material page. At the bottom of the Selected Material Ground Overlay section are two bump map parameters, Bump Intensity and Bump Map Texture.

109. Select Texture Operations beside Bump Map Texture and Create Texture.

110. The default texture is Fractal Noise with a Size of 1 meter along the X, Y, and Z axes.

111. Render a right view preview and let's see what it looks like. Even with just the default texture, polygon edges are less visible and the terrain looks more like ground.

112. Increase the Bump Intensity to 500%.

113. Render the right preview. Polygons are almost entirely gone.

114. Go back to the Terrain Parameter Editor and change the Maximum Fractal Depth to 0

115. Render the right preview again. The low Fractal Depth preview rendered faster and we still can't see any polygons. In fact, the fast rendering bump preview looks better than the long rendering high Fractal Depth version we made earlier.

116. Go back to the Ground Editor and disable the Bump Map Texture.

117. Render the left view preview. There's little difference in render times, but a world of difference in whether the terrain looks like a computer generated 3D surface or real terrain.

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