Creating salt flats

[mcdronkz]

Disclaimer: I'm fairly new to Terragen 2, especially surfaces. Please explain like I'm 5.

I'm recreating the Bonneville Racetrack to use as background footage for automotive photography. It's going pretty well so far. Downloaded the required GeoTIFF files, got them all lined up, and I'm having a nice and accurate view now. It's great to be able to match the exact shape of the mountains at the salt flats in a few clicks!

This is where I am so far.

The hills need a more realistic surface, but that shouldn't be too difficult with some colors and fractal breakup. The salt has dark spots at the moment which I think may add to the realism, but they should be looking way less obvious. A few clouds would be nice too. Some tweaking and it will look great!

My main challenge is creating the salt. It has to be as photorealistic as possible. It has to look like this. What's the most effective way to go about this?

I tried to create it using the Power Fractal v3, but I can't get the scale right, it ended up looking like sand dunes. Which nodes and settings will be important?

Any help is greatly appreciated!

[Hetzen]

One of the most important things to do in TG, is to understand the scales in the Power Fractal (PF). In its simplist form...

Feature Scale is the mountain to the Lead-in Scale mountain range, and Smallest Scale is the detail.

In the case of your salt flat texture, the feature scale and lead-in scale will be pretty much the same, as it's a consistant bump texture of around 2cm or 0.02m. The height of the displacement is set in the displacement tab.

The nice thing about working in TG is being able to use life scale to help you design your image, so have a look at your .ter and determine if it's covering the right area on the TG planet. Adding a sphere object with a reference diametre is a quick way of seeing if things are working right.

In the tweak noise tab in the PF, set your noise flavour to Perlin Billows. This is the same shape as Perlin, except any value that is negative (imagine a sine curve traveling bellow the x-axis), is inverted and becomes positive, giving you bumps with tight valleys. Perlin Ridges is Billows turned upside down.

Get used to navigating around your scene with the mouse and Alt key. It's liberating being confident in moving the camera to where you want to work. The three little icons on the end of the set camera button under your main viewport are worth getting used to in helping with this.

See where all that takes you...

Cheers

[Oshyan]

I made a quick version of this that you can paste into your scene to get started. Just copy all of the following text, go to your TG2 node network view, and Ctrl-V/Paste and the nodes should show up. Then connect the Input of the Power Fractal to your Terrain output/Base Colors shader, and the output of the Default Shader to the input of your Planet. The Default Shader is just there to provide a translucency effect which softens the appearance of the surface, it's optional but I think it looks more like the reference.

<terragen_clip>
   <default_shader
      name = "Default shader 01"
      gui_use_node_pos = "1"
      gui_node_pos = "-780 140 0"
      gui_group = ""
      enable = "1"
      input_node = "Power fractal shader v3 01"
      gui_use_preview_patch_size = "0"
      gui_preview_patch_size = "1000 1000"
      diffuse_colour = "0.5 0.5 0.5"
      colour_image = ""
      colour_function = ""
      translucency = "1 1 1"
      translucency_image = ""
      translucency_function = ""
      luminosity = "0 0 0"
      luminosity_image = ""
      luminosity_function = ""
      reflectivity = "0 0 0"
      reflectivity_image = ""
      reflectivity_function = ""
      reflection_tint = "1 1 1"
      index_of_refraction = "1.5"
      specular_roughness = "0.2"
      specular_roughness_image = ""
      invert_specular_roughness_image = "0"
      specular_roughness_function = ""
      displacement_direction = "1"
      displacement_multiplier = "0.01"
      displacement_image = ""
      displacement_function = ""
      displacement_offset = "0"
      opacity = "1 1 1"
      opacity_image = ""
      use_alpha_channel = "0"
      invert_opacity_image = "0"
      opacity_function = ""
      alpha_from_colour = "0"
      alpha_key = "0 0 0"
      key_tolerance = "0.1"
      image_projection = "4"
      projection_camera = ""
      unpremultiply_colour = "1"
      unpremultiply_translucency = "0"
      unpremultiply_luminosity = "0"
      unpremultiply_reflectivity = "0"
      unpremultiply_specular_roughness = "0"
      >
   </default_shader>
   <power_fractal_shader_v3
      name = "Power fractal shader v3 01"
      gui_use_node_pos = "1"
      gui_node_pos = "-920 220 0"
      gui_group = "Shaders"
      enable = "1"
      input_node = "/Base colours"
      gui_use_preview_patch_size = "0"
      gui_preview_patch_size = "1000 1000"
      seed = "53248"
      feature_scale = "0.03"
      lead-in_scale = "0.075"
      smallest_scale = "0.01"
      noise_octaves = "4"
      apply_high_colour = "1"
      high_colour = "0.949000001 0.9322999716 1"
      apply_low_colour = "0"
      low_colour = "0.7132143378 0.7412196398 0.7624999881"
      colour_contrast = "1"
      colour_offset = "0"
      colour_roughness = "1"
      clamp_high_colour = "1"
      clamp_low_colour = "1"
      apply_displacement = "1"
      displacement_direction = "1"
      displacement_amplitude = "0.03"
      displacement_offset = "0"
      displacement_roughness = "0.9375"
      displacement_spike_limit = "0.9375"
      continue_spike_limit = "0"
      adjust_coastline = "0"
      coastline_altitude = "0"
      coastline_smoothing = "30"
      noise_flavour = "0"
      noise_variation = "0.25"
      variation_method = "2"
      buoyancy_from_variation = "0"
      clumping_of_variation = "0.13125"
      noise_stretch_XYZ = "1 1 1"
      distort_by_normal = "0"
      distortion_by_normal = "5"
      lead-in_warp_effect = "0"
      lead-in_warp_amount = "0.5"
      less_warp_at_feature_scale = "0"
      allow_vertical_warp = "0"
      blend_by_shader = "0"
      blending_shader = ""
      fit_blendshader_to_this = "0"
      invert_blendshader = "0"
      >
   </power_fractal_shader_v3>
</terragen_clip>

Attached is an example of what this looks like from a ~2m camera position. Note also, do not reduce the Smallest Scale any further as it will probably cause render errors.

- Oshyan

[mcdronkz]

Wow, what a great response! Thanks a lot!

Hetzen: I will be experimenting with it tomorrow, I came back to post what I end up with!

Oshyan: That's fantastic! I've got it working already, looks very very close!