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7 <title>Height Maps</title>
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13 <p align="center"><font size="5">Height Maps</font></p>
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15 <table border="1" cellspacing="1" width="100%" bordercolor="#808080" bgcolor="#000000" cellpadding="10">
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18 <p> The terrain maps in Quake III: Team Arena began as grayscale bitmap art files
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19 imported into David Hyde
\92s
\93<i>GenSurf</i>
\94 tool, a Q3Radiant plug-in. As
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20 mentioned before, the height map is a template that the utility uses to define
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21 the vertex heights of the triangles forming the terrain surface. We used <i> Adobe
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22 Photoshop</i> and <i> JASC
\92s Paint Shop Pro</i> to create and adjust our height maps
\85\r
23 but any art program that can output a .bmp format file can be used to create the
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25 </font><font FACE="Times New Roman" SIZE="2">
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26 <p><img SRC="Image3.gif" WIDTH="264" HEIGHT="350" align="left"></p>
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27 </font><font FACE="Times New Roman">
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29 <p> By way of example, the piece of artwork in figure 1 is a greatly scaled up
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30 (4X) version of the height map used to create the initial terrain geometry for
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31 mpterra2. The very dark, horizontal area near the center is the big
\93lake
\94\r
32 near the center of the map. The dark curves to the upper right and lower left
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33 are the
\93fjord
\94 water areas. The dark areas in the upper left and lower
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34 right are the locations of the bases. The white and very light gray areas
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35 represent the peaks of hills and mountains.</p>
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36 <p> The key to understanding how the height map works is that the shades of gray
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37 in the art (call them
\93color values
\94) represent the height of mesh vertexes
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38 (triangle corners) and not the triangle quads (squares created by two
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39 triangles). When you work on a piece of art where each individual pixel
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40 corresponds to a vertex, it is easy to imagine the pixels (usually large square
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41 blocks) as squares of terrain. But that
\92s not how it works.</p>
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42 <p> Start by giving some thought to the eventual size and proportions of the
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43 final terrain area in your map. How many rows and columns of triangles do you
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44 want in the map? The finer you subdivide the map (making more rows and columns),
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45 the more triangles will appear in any given view, but the terrain can be made
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46 less blocky by including more.</p>
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47 <p> GenSurf can generate a terrain mesh of up to 64 triangles on a side (of the X
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48 and Y dimensions of the entire mesh). If you don
\92t decimate the GenSurf output
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49 (an option that optimizes and reduces the number of triangles used to create the
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50 mesh
\85 and we really recommend that you don
\92t), it generates a mesh of
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51 triangles in arranged in quads in neat rows and columns. By way of reference,
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52 mpterra2 (the largest Team Arena map) is
\93only
\94 48x64 columns and rows of
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53 triangles. Since Q3Radiant and q3map tend to like things that end up in neat
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54 powers of 2 or units of 64 subdivisions, consider having your map extents (lower
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55 left and upper right map corners) fall onto neat units, power of 2 units. In
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56 mpterra2, the extents were set up to make the mesh triangles have sides of 256
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58 </font><font FACE="Times New Roman" SIZE="2">
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59 <p><img SRC="Image4.gif" WIDTH="103" HEIGHT="99" align="left"></p>
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60 </font><font FACE="Times New Roman">
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62 <p> Figure 2 shows an example of a top view of a terrain mesh that is 8 x 8 rows
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63 and colums of triangles (on a side).</p>
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64 <p> Just as you would plan out a game map, give thought to the layout and flow of
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65 your terrain map. Will it be all-open in one view? Can you use natural terrain
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66 features to block vis? How complicated will your buildings (if any) be? Do you
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67 want to include trees, water, weather effects or other items that could add to
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68 the visual cost of your map?</p>
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69 <p> Begin the creation of your height map by making a new grayscale file. If your
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70 program doesn
\92t allow you to easily modify a .bmp format file, work in another
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71 format and then convert it when you save. You can make the dimensions of your
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72 height map art whatever you want. The extents you set in GenSurf for the map
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73 dimensions are what determine the final size of the terrain piece. Some may find
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74 it easier to work with a large file initially, using their favorite painting
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75 tools to lay in the shades of gray.</p>
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76 <p> However, when you get down to making final and precise changes in your height
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77 map you should (and this is STRONGLY recommended), change the size of the art
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78 file such that the pixel dimensions of the map are 1 pixel larger than the
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79 number of divisions (rows and columns) in the terrain mesh you want to create.
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80 If you are making a 64 x 64 division map, then you want to create a 65 x 65
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81 pixel height map.</p>
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82 <p> If there is not a one-to-one match between the number of vertexes in the mesh
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83 (one more than the number of divisions) and the number of pixels in the height
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84 map, then GenSurf interpolates the number values (0 to 255 range) of the pixels
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85 to get an averaged value instead of an exact value for the height of the vertex
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87 <p> When you save out the height map art file, you must save it in 8-bit .BMP
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88 format. Currently, this is the only the file format that GenSurf recognizes.</p>
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90 <p>Tips and things to consider for making Height Maps</p>
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93 </b></font><font FACE="Symbol">
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94 <p>· </font><font FACE="Times New Roman">Read through the section on blocking
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95 vis later in the document. Plan your vis blocking terrain structures in advance
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96 instead of having to start over when you discover that too much of your world is
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98 </font><font FACE="Symbol">
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99 <p>· </font><font FACE="Times New Roman">Consider what type of geometry will
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100 form the edges of your map. The terrain maps in Q3:TA resolve the issue by
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101 creating canyon-like settings
\85 valleys bordered by high canyon or mountain
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103 </font><font FACE="Symbol">
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104 <p>· </font><font FACE="Times New Roman">Start by filling your map with a
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105 neutral gray (value 127 or 128). Paint the high areas lighter and the low areas
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107 </font><font FACE="Symbol">
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108 <p>· </font><font FACE="Times New Roman">Keep your terrain shapes simple when
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109 you start. You can add greater complexity as your map develops.</p>
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110 </font><font FACE="Symbol">
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111 <p>· </font><font FACE="Times New Roman">You will probably want to keep the
\93playable
\94\r
112 area of your map within a fairly close or
\93narrow
\94 range of gray values
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113 close to the middle range of values. This allows you to use very dark shades of
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114 gray to create deep chasms and very light shades of gray to create high
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115 mountains, canyon walls or visual barriers.</p>
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116 </font><font FACE="Symbol">
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117 <p>· </font><font FACE="Times New Roman">Extreme jumps between the gray values
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118 in adjacent areas means steep slopes.</p>
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119 </font><font FACE="Symbol">
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120 <p>· </font><font FACE="Times New Roman">Avoid making vertical or near vertical
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121 terrain surfaces
\85 unless you don
\92t mind the resulting textured surface
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122 looking like barcode. Q3Map planar projects the textures onto the terrain entity
\92s
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123 surface (Normal brushes are box mapped). The pixels will stretch and stretch to
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124 fill the space. The farther the surface is from horizontal, the greater the
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126 </font><font FACE="Symbol">
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127 <p>· </font><font FACE="Times New Roman">Use the roughness feature of GenSurf
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128 to add a little, um
\85 roughness to your map
\85 so flat areas aren
\92t
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129 completely flat. If you are using a 1 to 1 scale height map, adding
\93noise
\94\r
130 to the file will also accomplish this.</p>
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131 </font><font FACE="Symbol">
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132 <p>· </font><font FACE="Times New Roman">If you want an area, such as a path,
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133 to be flat, you need to make the gray value affecting two adjacent vertexes the
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135 </font><font FACE="Symbol">
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136 <p>· </font><font FACE="Times New Roman">You can create gentle slopes by
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137 changing the gray values between adjacent areas by very small amounts.</p>
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138 </font><font FACE="Symbol">
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139 <p>· </font><font FACE="Times New Roman">Slopes greater than 45 degrees are
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140 close to becoming unplayable barriers.</p>
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144 <p>If you are building a symmetrical team style map, only create one side of the
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145 terrain. Create a new piece of art that has the dimensions of the final piece.
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146 Paste the map half into the new file and move it into position. If the map will
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147 have an even number of vertexes, paste the map again and then rotate or mirror
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148 (as you choose) the selection and move it into position. If the number of
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149 vertexes is odd, after you paste the first half of the map, select all but the
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150 row or column of pixels along which the two halves of the map will face and copy
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151 it. Paste it, rotate or mirror it, then position it. Now, select and copy half
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152 the row or column of pixels you didn
\92t copy in the last operation. Paste it,
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153 transform it as you did in the last operation, and then position it so that it
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154 is in the same row or column, but on the opposite side of the piece you copied.</p>
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155 <p>When you make significant changes to a height map, consider saving it as
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156 version rather than over-writing the older file. Always nice to have a back up
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157 when you realize that you
\92ve messed up more than you
\92ve fixed.</p>
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160 <p align="center"><a href="creating_the_terrain.html">Back</a> - <a href="table_of_contents.html">Table
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161 of Contents</a> - <a href="other_possible_height_map_tools.html">Other Height
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169 <p align="center"> </p>
\r
170 <p align="center">-8-</p>
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projects / xonotic / netradiant.git / blob