Creating HDRI
Backgrounds Creating HDRI
Backgrounds When an HDRI background is imported, it behaves as if an infinitely large, textured, sphere or cube was centered on the model. The virtual sphere or cube is so large that view position changes do not affect its display. However, view orientation changes do affect which part of the image is shown in the background; this provides a true 3D sense to the model. One bounce of indirect lighting is generated with HDRI lighting.
By default, an image environment background renders as both a background and a light source. However, it is possible to use one HDRI background resource as an environment background, and another for environment lighting; see Setting Lighting Options. Several Renderworks styles incorporate the use of an HDRI background.
Purpose of HDRI Background Resource |
Creation Method |
Use an HDRI background resource as both environment background and environment lighting |
Create an HDRI background resource and apply it to the layer. By default, the Layer Lighting Options is set to use the lighting from the current background. |
Use an HDRI background as environment background only |
Create an HDRI background resource and apply it to the layer. In the Layer Lighting Options dialog box, specify None for Environment Lighting. |
Use an HDRI background resource as environment lighting only |
Create an HDRI background resource, but do not apply it to the layer. In the Layer Lighting Options dialog box, select From Selected Background and specify the resource. |
Use one HDRI background resource as an environment background and a different background resource for environment lighting |
Create the first HDRI background resource and apply it to the layer (environment background). Create the second background resource but do not apply it to the layer. Instead, in the Layer Lighting Options dialog box, select From Selected Background and specify the second resource (environment lighting). |
HDRI backgrounds render best in Perspective projection. In Orthogonal projection, HDRI backgrounds are suitable for lighting and reflections, but appear as a single background color because of the narrow field of view.
If the HDRI background includes a sun in its image, and the drawing also contains directional lights, the light directions may not match, creating multiple shadows.
To create an HDRI background:
1. Create the background resource as described in Creating Layer Backgrounds.
2. Select Image Environment (HDRI) from the Background list.
3. Select the .hdr image file to use. The image is automatically converted to Lat/Long format. An OpenEXR file can also be used; it must be in Lat/Long format.
The Edit Image Environment (HDRI) Background dialog box opens.
Click to show/hide the parameters.
4. Set the parameters and click OK to use the image as an environment background resource.
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