Setting up a cloudy environment

From Eclat-Digital Ocean 2014 Documentation
Jump to: navigation, search

In this tutorial, we will see how to change the environment lighting in the scene.

Environment lighting describes the way your scene is lit from a very far distance, as opposed to the light emitted by the scene objects themselves. It is a very convenient way to simulate a sky light for outdoor scenes, but can be also be used in other situations.

Before starting

You should have already exported your scene with SketchUp or Rhinoceros to an ocxml file. If not, load a SketchUp file or follow Exporting a Rhinoceros scene to Ocean 2014

You may also load the scene file exported at the previous tutorial : cloudenv-start.ocbin

Modifying the default environment


The Rhinoceros exporter created a default environment, generally called uniform or skylight. You may find it in the object list toolbox.

Create a new environment by clicking on the environment-2014.png button in the toolbox, and name it overcast

Using an HDR environment map


HDR environment maps (envmaps) are high dynamic range, spherical pictures of the environment, and are widely used in computer graphics for realistic lighting. Ocean accurately computes the lighting produced by these environment maps, each pixel being virtually used as an independant light source.

There are many commercial HDR envmaps available for purchase. We provide you a few low resolution envmaps for download : scatter-morning sunny cloudy overcast

In this example, we will reproduce a cloudy sky environment, using this one.

The HDR envmap can be used as an environment, by setting the environment type to envmap:


The base child node is a spectrum, and is set by default to a 6500K blackbody. Just click on it and set the gain parameter to 1E-4. This setting changes the overall lightness of the sky, it is not very important as the default camera adjusts its gain automatically in post-processing steps, but starting with plausible value is better.


Then click on the image child node and set it to the path of the HDR image (nantes-overcast.exr)

Finally, click on the "Apply" button at the bottom of the edit window.

Now select the overcast environment in the render settings toolbox.

You may now start the render and obtain the following picture after a few minutes:


Next steps

In the next tutorial, you will see how to use existing packaged materials in your scene : Using external library materials in your scene

See also