View source for Tutorial 1: Creating Your First Scene

=== Adding Grass ===

Now that we have dirt, let’s add some grass. We’ll add the grass as another layer. Click the '''Add Layer''' button at the top of the node list and select '''Surface Layer''' from the drop-down menu.

[[File:FirstScene_-_Add_surface_layer.jpg|border|700px|Adding a surface layer]]
<br><br>
 
Surface layers default to having full coverage and a middle-grey colour, so your terrain will immediately turn completely grey. The newly-added surface layer should be automatically selected in the node list, but if it isn’t, click '''"Surface layer 01"''' from the node list to select it. 

[[File:FirstScene_-_Surface_layer_01.jpg|border|700px|The newly-added layer selected]]
<br><br>

First off, click the '''Name''' field and change this to something descriptive, like "Grass". This will make it easy to keep track of our layers when we add more. Next we’ll adjust the color. The color settings here work the same as they do in the "Base colours" node except that there is only one color. Click the '''current colour''' box on the '''"Apply colour"''' line to choose a new color. Pick something greenish-yellow with low-medium saturation. (RGB 102, 119, 27 is a good color to start with.)

The color is looking good, but we don’t want grass to cover the whole scene. Select the '''"Altitude constraints"''' tab. 

[[File:FirstScene_-_Altitude_Constraints tab.jpg|border|700px|The altitude constraints tab]]
<br><br>

This tab allows you to constrain this layer to a specific height range with the "Limit maximum altitude" and "Limit minimum altitude" properties. These values are in meters. For the grass, we’re only going to worry about the maximum altitude. To start, check the '''"Limit maximum altitude"''' box to enable this property. You should now see the brown tops of the mountains poking out above the grass. The '''"Maximum altitude"''' might be fine at 1000, or you might want to tweak it a bit (though these are tall mountains, so at anything below 800 your grass layer might be hard to spot in the mountains). The "Max altitude fuzzy zone" is pretty good at its default value of 200, so let’s leave that as-is for now. (If you want to play with it, this value defines the altitude range that is used to transition between where the layer is fully visible and where it disappears completely at the maximum altitude. Think of it like a gradient tool. So with a maximum altitude of 900 and a fuzzy zone of 200, the altitude range between 700-900 is used to “fade out” the grass layer and show the layer beneath.) 

You should now have mountains with grass growing up their slopes, but the line where the grass ends probably looks unrealistically uniform. We’ll fix that in our next step. Select the '''"Slope constraints"''' tab. 

[[File:FirstScene_-_Slope_constraints tab.jpg|border|700px|The 'Slope constraints' tab]]
<br><br>
 
Enable '''"Limit maximum slope"'''. This will limit the maximum slope angle (in degrees) that this layer will be applied to. Set the '''"Maximum slope angle"''' to about '''25''' with the '''"Max slope fuzzy zone"''' (also in degrees) at about '''10'''. You may wish to test your settings in an actual render (Ctrl+R/Cmd+R).

The grass layer is starting to look more natural now, but it still looks a bit too uniform. We’ll address this in the '''Coverage/Breakup''' tab. Select this tab to view the options.

[[File:FirstScene_-_CoverageBreakup_tab.jpg|border|700px|The Coverage/Breakup tab]]
<br><br>

There are two settings we’ll be changing here: Coverage and "Fractal breakup". Coverage controls how thoroughly the layer will cover the areas where it appears. Think of it like changing the transparency of the layer, where 1 represents 100% (total coverage), and 0 represents 0% (the layer isn’t visible). Let’s dial the coverage back a bit, with a value of '''0.7''' for '''Coverage''' (i.e. 70% coverage).

'''"Fractal breakup"''' breaks up the surface with an appearance of randomness to its texture. Values between 0 and 1 will tend to produce fairly natural results, with 0 being equivalent to turning off the effect entirely and 1 being a smooth distribution. (Values above 1 will make the effect sharper, which can be the right look for some layers, but not for our grass layer.) Set the '''"Fractal breakup"''' to '''1.0''', which should look right for grass.

{| class="wikitable"
|'''Note:''' If you’re familiar with Terragen Classic, "fractal breakup" works similarly to "fractal noise".
|}

Do a render of the current scene to get an idea of how different it now looks.

[[File:FirstScene_-_Shaders_grass_dirt_render.jpg|border|The scene with grass and dirt]]
<br><br>