Photo-Realistic Rendering

Where your goal is to produce realistic images of your models, you can use the Vue rendering engine. This takes into account both direct and indirect lighting, such as reflection of light and refraction. Additionally, it can calculate diffuse reflections and caustics (such as reflected light, and refraction). For these two features, in particular, the following points should be kept in mind:

You should use real world working units for your model, and lighting values are input as lumens.
IES lighting files should be used to correctly display the lighting characteristics of different lamps, such as halogen lamps, incandescent lamps, or fluorescent tubes.
Care has to be taken when defining materials, to ensure that realistic values are defined.
You should set the display gamma value for your output.

Gamma Correction for Photo-Realistic Rendering

Gamma correction is used to compensate for the fact that monitors and printers do not have the same visual response as the human eye, and serves to bring out more detail in darker areas of images. The gamma correction for a typical monitor should be set to 1.5 to 2.5. You can set the gamma correction value for your display in the View Options category of the Preferences dialog ( File > Settings > User > Preferences ). An "exact" figure is not critical, but a good starting value to experiment with is 1.7.

Note: Beginning with this release, the default gamma correction is 1.7, rather than 1.0 as in all previous versions.

Similarly, when you save an image, you have the option of applying Gamma Correction to it. This may be to accommodate a printer in order to produce hard-copy output that more closely represents what is seen on the screen. As a rule, to avoid "tying" your image to one particular display/printing device, it is better to save images with a neutral gamma value (1.0) and let other software or printing device software add the gamma correction that they require. Each display/printing device can have different characteristics such that the correct gamma correction for one device may not be correct for another. Once gamma correction has been saved with an image, changing the gamma value will not let you return the image exactly to its original state (with gamma correction of 1.0).

There is, however, one proviso. You can perform a better gamma correction while you still have floating point brightness values, before they are saved in a typical integer brightness file format. What this means is, if you have a specific display or output device to cater for, it may be advantageous to save the image with a gamma correction value (other than 1.0). While this ties the image to the output device, it may also give the best result. Matching your save image gamma to your system display gamma is a good idea. By matching display gamma to save image gamma, what you see on your monitor's screen is what you will get in your saved image.

Typically, printers tend to darken images more than display monitors, so a higher value may be required if you intend to print the finished image. Where required, gamma correction can be performed on the saved image, after rendering, using the image display utility or other imaging software.