Environment Tab

Enviroment icons

Toggle Sky: The background is a clear sky that changes automatically according to the position of the sun. If a background image is not used, it is disabled.
Toggle Sun: Creates a sun that produces the same shadows as in a SketchUp model.
Toggle Ground Plane: Toggles on/off a ground plane that catches shadows and reflects objects.
Toggle Preview Widget: Hides/Unhides the Preview Widget. The widget gives a preview of the environment and updates automatically. When Manual Sun is disabled and IBL lighting is being used, you can rotate the environment maps by dragging the preview image.

Sun / Ground/ Sky Tab

Manual Sun

By default, the intensity, position, and spectral color of the sun are handled automatically, based on the shadow settings in SketchUp. The Manual Sun option lets you override these settings.

When Manual Sun in enabled, you can modify the softness of Sun shadows with the multiplier, power, and emittance settings.

If you want complete control over the Sun's position regardless of SketchUp's Shadow settings, disable "Use SketchUp Sun position." You can adjust the sun Polar Angle and Azimuth, either by entering the desired values or by opening the Environment Preview Widget and clicking the preferred location in the preview.

Ground Settings

The Ground settings let you control the way the ground plane reflects light. You can specify roughness of the reflections as well as their intensity (%) and color.

Sky Settings

The Sky settings affect the appearance of the Thea Physical Sky. The most important parameter is Turbidity which requires a value of approximately 2.5 for a clear sky and close to 10.0 for an overcast one.

IBL Tab

Use the IBL Tab to specify the Illumination, Background, Reflection, and Refraction maps.

Image‐Based Lighting is a convenient way to add illumination to your scene. A photo of a real scene can be used, to create highly convincing lighting and enhance the realism of your renderings. In most cases, you need to use High Dynamic Range images to provide sufficient
lighting.

You can use one image for illuminating the scene or set up different images for the background, reflections, and refractions. This makes it possible to use different sources for lighting and for the background/reflections, which in most cases need more detailed images. This is actually standard practice: the illumination source is a relatively low‐detailed texture so that the image can quickly “converge,” while the background and reflections use a detailed map for visually enhanced results.

To add an image, select the type, and click the s button to select the desired image. When a bitmap is selected, its path is displayed next to the button. You can control the Intensity, Rotation, and Wrapping (the way the image is wrapped around the model).

There is also an option to use a pure color for an IBL slot. You can access this option by clicking on the image icon and selecting 'Color.' From this menu, you can also remove the image currently loaded in the slot by selecting "Remove Bitmap."
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Global Medium

Medium Type (Fog)

With the Fog preset, you can achieve model-wide volumetric effects. Using the Cloud preset, volumetric effects can be created within a specified volume.
Fog Density: Control the thickness of the fog.
Top/Bottom Level (m): Define where the fog starts and ends.
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Medium Type (Custom Medium)

When you switch to Custom Medium, the entire modeling space is filled with a global medium, which can be tweaked using the Absorption Color, Scatter Color, and Index of Refraction parameters. Please note that Sky, IBL, and Sun don't work in this mode due to the global nature of the medium.
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