Menu bar

There are just four menus in the menu bar: 'File', 'Render', 'View' and 'help'.

File

• Open - this lets you open a file with the .lxs extension
• Resume FLM - this lets you open a file with the lxs extension and restart it where you had stopped it if it finds a corresponding file with the flm extension
• Load FLM - this allows you to open a file with the flm extension (luxrender virtual film) and apply postprocessing effects on it
• Save FLM - this allows to force luxrender to write its virtual film to a file with the flm extension, even if it hadn't been configured in the render settings
• Exit - this exits the program
  

The rendering is saved at regular intervals automatically and there is no other save button available currently.

Render

• Resume - resumes the rendering process after it has been paused
• Pause - pauses the rendering process
• Stop - stops the rendering process once a safe stop point has been reached (to ensure all parts of the picture will have received an homogeneous number of samples)
  

The functionality of this menu can also be accessed by using the buttons at the top left of the render tab.

View

• Tool Bar - hides/shows the toolbar in the Render tab
• Status Bar - hides/shows the status bar
• Side Pane - hides/shows the side panel in the Render tab
• Rulers - selects the rulers to display in the preview area of the Render tab
  • Disabled - no ruler is shown
  • Pixels - rulers graduations will be in pixels
  • Normalized - rulers graduations will be in percentage of the image size
• Pan Mode - holding down the left mouse button in the preview area of the Render tab will allow you to move the preview around (this option is also available at the right of the Render tab tool bar)
  
• Zoom Mode - holding down the left mouse button in the preview area of the Render tab will allow you to select an area to zoom in (this option is also available at the right of the Render tab tool bar)
• Copy - copies the current preview image into the clipboard (without alpha channel)
• Clear log - deletes all messages from the Log tab
• Full Screen - removes all window decorations and only displays the preview over the whole screen (use Ctrl+F to go back to windowed mode)
  

Help

• about - displays a screen with the version of LuxRender you are using, the names of the developers and the address of the LuxRender website.

Render tab

The rendering preview tab shows a preview of the rendering. This allows you to monitor the rendering and stop it when it has reached the quality you expected.

In pan mode, holding the left mouse button and dragging pans the view; pressing the middle mouse buttons zooms to fit the screen; the mouse wheel zooms in or out; the right mouse button zooms to 100%.

In zoom mode, holding the left mouse button allows you to select an area to zoom in; other mouse buttons have no effect.

Tool bar

Apart from the rendering preview, there are a couple of buttons in this tab.

On the left, there are buttons to:

• resume the render
• pause the render
• stop render after an homogeneous number of samples has been gathered across the image
• change the number of threads used to render(for fastest results, set this to the number of processor cores that are available on your computer, typically one, two or four)
• copy the current preview to the clipboard (without alpha channel)

On the right, you 'll find buttons to:

• select pan mode
• select zoom mode
• select an area of interest (this last one has no effect currently).

Imaging option panel

This is where you'll be able to fine tune global post processing effects. Let's review all the available options.

Groups have a triangle on the right allowing you to fold or unfold the group. Some have a power symbol that allows you to disable the effects contained into the group.

Tonemap

This group of options will allow you to select the method used to convert the high dynamic range picture computed by LuxRender to a low dynamic range version displayable on your screen.

• Reinhardt - general purpose method that will automatically adjust the display to the intensity of the scene (ie, if you replace a 100W light in your scene by a 1000W, the result will look the same)
• linear - camera style method with f-stop, exposure, et al that will mimic the behaviour of a digital camera, the EV value displayed on the status bar should help you set its parameters if you have some basic photography knowledge
• Contrast - this method will try to preserve the contrast of the image as much as possible, a slider allows you to tweak the brightness of the result
  
• Max white - this method will scale the whole picture intensity so that the pixel the the highest intensity will be mapped to white, if you have pixels with abnormally high intensities, the picture might be mostly black when using this method

Lens effects

This will allow you to apply various effects like bloom or vignetting.

• Gaussian bloom - this will spread light following a gaussian pattern, you can specify the amount of light to spread and the radius (in % of the screen) of the pattern
• Vignetting - this is a simple adjustable vignetting effect
• Chromatic aberration - this will simulate the color shift caused by the dispersion of light in the lens system of a camera
• Glare - this will simulate the diffraction of light due to the diaphragm blades of a camera, much light glare, you can specify the amount of light to spread, the radius of the pattern and the number of blades

Bloom and glare effects are quite demanding, so they aren't computed everytime the screen preview is refreshed nor when the render is saved to disk, but only when you press the "Compute layer" button. The "Delete layer" button allows you to remove the effet.

Colorspace

LuxRender is a fully spectral renderer, meaning that it has no knowledge of an RGB color, so you must tell him how to convert light data to an RGB color for the display you're using. There are some standard defining display devices properties like sRGB, but usually each display device has its own set of characteristics available from the manufacturer or some calibration utilities.

For optimal results we recommend that you configure the colorspace to match that of your display, but sRGB is a good default for computer screens, while NTSC or PAL presets should be adequate for video output.

Gamma

This will allow you to the linear intensity of the computed image to something closer to the human eye perception of intensity. The default 2.2 should fit most cases.

HDR histogram

You'll find here a set of histograms that should allow you to check that your settings are adequate.

Noise reduction

Thanks to the GPL license upon which it is distributed, LuxRender can embed the powerfull noise reduction algorithms from the GreyCStoration library. We refer you to the documentation of the library for the various parameters of those algorithms.

LightGroups option panel

For each light group that your 3D modeller has exported, you'll be presented with a set of adjustable parameters to tweak the lighting of your render in real time. The triangle on the right allows you to fold or unfold the parameters of the light group. The power symbol allows you to enable or disable the display of the light group, you can use it to instantly create a night render from a daylight render.

• Gain - this is a simple power adjustment slider
• RGB - allows you to multiply the light color with an RGB color to experiment with various lighting conditions
• Black body temperature - allows you to get warmer or colder light (it uses a standard D65 daylight white point as a reference)

Log tab

This tab shows log messages that are output during the rendering process, including:

• information about loaded bitmap images
• information about rendering progress
• information about writes to disk
• information about network activity

Network tab

This tab presents you with a list of currently registered network server upon which the rendering will be distributed.

The tool bar allows to add or remove hosts. You can either use a name or an IP address and you can specify a non default port by putting a colon in-between.

During rendering, the server list will also display statistics on the various nodes.

The update interval parameter in the tool bar allows you to tweak the frequency of the updates to the displayed information in seconds. Be careful that using a too small value might make the interface difficult to use.

Status bar

This bar displays information about the state of your rendering; from left to right:

• Total elapsed rendering time
• Current raw rendering speed in samples per second
  
• Averaged rendering speed including all network nodes
• Averaged number of samples per pixel
• Averaged efficiency (number of light contributions gathered with a single sample) in %, a value of 100% means that each sample brings 1 light contribution to the final image on average
• Exposure value for the current render, this will allow you to fine tune the linear tonemapper with some standard photographic indication