From Terragen Documentation from Planetside Software
Revision as of 13:33, 2 March 2020 by Matt (talk | contribs) (Updated for v4.5.05.)
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We are currently working on integrating OpenColorIO (OCIO) into Terragen. This feature is in closed beta testing. If you're using a version of Terragen with OCIO options we hope you find this page useful. It will be updated as our OCIO features are worked on.


1. Set up OCIO on your computer

If you're working at a company that uses OCIO, this has probably already been done for you.

If you don't have OCIO set up, follow these instructions:

  1. Download the OCIO Configurations from the OCIO website: Download on the .zip link on that page.
  2. Extract the contents of the .zip file to your computer.
  3. Decide which configuration you want to use. We recommend the aces_1.0.3 configuration. You should see a file called config.ocio inside each of the configuration folders.
  4. Set an environment variable in your system called OCIO. The OCIO variable should be set to the full path and filename of the config.ocio file you want to use.

2. Restart Terragen after you change environment variables that affect OCIO

3. Enable OCIO in your Terragen project

In Terragen, OCIO is enabled or disabled on a per-project (per-scene) basis. Click on Project Settings at the lower left of the main window, then turn on Use OCIO if it is not already on.

First Tests

Toggling "Use OCIO" in Project Settings should cause the 3D Preview to refresh. If OCIO is configured correctly on your computer then you should also see the colours change in the 3D Preview. The difference may be subtle, but this depends on the OCIO configuration and the default choices for "Rendering space" and "Display space".

When "Use OCIO" is enabled, rendered images should also look different in the Render View.

You can change the "Rendering space" but this should usually be "scene_linear" or "rendering". The former is more likely to be compatible with a wide range of OCIO configurations, and this is what Terragen chooses by default.

You can change the "Display space", but this should match your monitor. Terragen defaults to whichever display/view the OCIO configuration says is the default. Often this is "sRGB", but if you're unsure what to use then check with the person who set up your OCIO configuration.

What's Supported in v4.5.05

  • The user can choose the rendering/working space from the roles defined in the OCIO config. It defaults to "scene_linear", e.g. "scene_linear (ACES - ACEScg)".
  • The user can choose the display/view space from the displays/views defined in the OCIO config. It defaults to whichever display/view the OCIO config says is the default, e.g. "sRGB (ACES)"
  • 3D Preview refreshes when toggling OCIO checkbox or changing colour spaces in Project Settings.
  • Render View refreshes when toggling OCIO checkbox or changing colour spaces in Project Settings.
  • HDR renders are interpreted using whichever "Rendering space" is selected.
  • LDR (display) version of the render is the result of tonemapping and transforming the HDR image using whichever "Display space" is selected.
  • The Render View displays the LDR (display) version of the rendered image.
  • Saving to an LDR file format (e.g. TIFF) saves the LDR (display) version of the image.
  • Saving to EXR saves directly from the raw HDR render. Therefore you should interpret EXRs according to whichever "Rendering space" is selected, e.g. "scene_linear (ACES - ACEScg)". We presume this is what you want if you are using Terragen in a multi-app OCIO workflow.

Not Yet Supported

  • Conversion of textures and other input colours. Until this is implemented you should expect textures to look different when rendering and viewing with OCIO. You may need to preconvert them.
  • Independent choice of colour space for internal rendering and file output. At the moment, EXRs are output using the scene linear values that were generated by the renderer.

Other Considerations

The default scene -- particularly the default atmosphere -- has colours which were chosen for a Rec. 709 (sRGB) pipeline. They don't know about your OCIO config. If you're using an ACES configuration, for example, you will find that the sky looks too green. We are going to figure out some new defaults for ACEScg, but you might find the following adjusments useful:

  • Bluesky horizon colour (on the Main tab): reduce the green channel very slightly so that it's closer to the red value than the blue value. For a less saturated look, simply make it greyscale 0.25 (135, 135, 135).
    • Our latest recommendation is (135, 135, 135)
  • Bluesky density colour (on the Tweaks tab): increase the red channel so that it's a little closer to the green value.
    • Our latest recommendation is (147, 178, 255)