LuxBlend Camera and Environment
From LuxRender Wiki
As its name suggests, the Cam/Env tab contains settings related to the camera and to environment lights. In addition, the scale of the scene can be set here.
LuxRender features four different camera types. Where possible, camera properties are linked to Blender's active camera, but a number of settings have to be set within LuxBlend.
The camera type can be chosen from the dropdown menu at the top of the window. For details and examples, please see the LuxRender_Cameras page.
The field of view can be set by either the active Blender camera or manually using focal length or fov angle values.
Near & Far clipping
Please see clipping for definitions and examples of this setting and it's uses. Start and end values can be taken from the active Blender camera or set manually and are listed in Blender units
Depth of Field & Bokeh
Depth of field can be set manually or automatically. The autofocus mode will focus on the object closest to the center of the view. The manual mode allows you to set the focal point by entering a numerical distance, or by selecting an object and clicking the 'S' button next to the distance box. The object mode allows you to assign an object as the 'focal point'.
Lens Shift & Aspect ratio
Please see Lens shift for a description and examples of this setting.
Motion blur can be set using either a still or cinema camera method. For still cameras, the shutter speed is listed in fractions of a second. For the cinema camera method, it is set using a shutter angle.
Environment lights can be used to light the scene on their own or in combination with emitters and lamps. Three different environment light types are available; only one can be used at a time. For details and examples, see the LuxRender_Lighting page.
The sunsky system uses the angle of a Blender sun object to create a combination of direct sunlight and ambient atmospheric light. The colour of the light depends on the sun angle.
The strength of the light can be set using the gain setting. The turbidity setting defines the clarity of the sky: setting it to two will result in a clear sky, while higher settings (up to 30) can be used to get the effect of a more cloudy sky. The size of the sun can be adjusted using the "rel. size", although for a realistic result the value should be one.
It is possible to change the sun direction by changing the rotation setting in LuxBlend. This has the same effect as rotating Blender's sun object around the z axis.
Selecting "infinite" in the environment tab on the Cam/Env tab will result in even lighting from all sides. The colour can be set in the "world" in Blender's shading panel, under world buttons.
Using an environment map, the scene will be lit from all sides, but the colour and intensity depend on the local colour of an image that is projected around the scene. To use an environment map, select infinite in the environment drop down menu and select the image you want to use.
Amongst others, the effect of this kind of lighting is visible in reflective materials. Best results are generally achieved by using a high dynamic range image (like OpenEXR). It is possible to use low dynamic range images (ie Jpeg or PNG) as environment maps, but in this case you may want to add some additional lighting to your scene to avoid getting a poorly contrast render. This is not necessary with HDR environment maps, which can be used as the only source of light to create a realistic lighting.
When using environment maps, using a gamma value of 1.0 (instead of the usual 2.2) is recommended.
You can find a lot of free quality HDR maps on the web by looking for "hdr maps"/"hdri maps" or "light probes".
Note : Be careful, despite the fact that ".hdr" files appear in the image selector, new versions of LuxBlend/LuxRender still support only OpenEXR format (along with traditional low dynamic range images, naturally). Using an .hdr file, while producing no error during export, will result in an error during the attempt to load the file before rendering, ending with no environment map being taken into account . If you have some ".hdr" environment maps you want to use, here' is a simple trick using Blender:
- Download file, unzip XYZ.hdr file into directory
- In blender's image editor window: Image -> open and select the XYZ.hdr file
- Still in image editor: Image -> Save As.
- Select OpenEXR from 'Save Image' combo box at bottom.
- Press 'Save Image' button. This results in XYZ.hdr.exr
- Open LuxBlend, infinite environment -> browse -> select XYZ.hdr.exr