Parameters of Bitmap or RGBE Import

When importing bitmap file and converting it as map, the map can be used as emittance for source definition.

Note: The emittance of a source describes how each point of a surface emits rays. For a source definition, the emittance can be uniform or described by a basic or a spectral map. In the case of a basic map you have to supply a spectrum for the source and this spectrum is the same for each point of the source. In the case of a spectral map, the spectrum for the source is generated from the color of each pixel of the bitmap.

Importing bitmap file is useful to define an environment around your system for a real rendering (luminance simulation).

Warning: There is an infinite possible spectrum for one color and the bitmap file import only provides a solution with three Gaussian spectrum centered on red, green and blue. In most cases, default options gives a good resulting XMP map.

Bitmap File

In Bitmap file box, you can change the bitmap file.

BMP Mask

A BMP Mask allows you to apply a mask onto a XMP map to hide specific parts of the map.

The parts to hide must be black in the BMP Mask. All other parts of the BMP Mask can be different from black.

The BMP Mask should be the same ratio as the XMP map to correctly place the black parts.



BMP Mask	XMP Map	XMP Map with BMP Mask applied

Map Type

In Map type group box, you must select the map type.

With Basic map, you can convert the selected bitmap into a basic xmp map.

With Spectral map, you can convert the selected bitmap into a spectral xmp map. In Wavelength minimum, Wavelength maximum, Wavelength Nb and Wavelength Step boxes, you must set values to define the wavelength's sampling for converting a color bitmap into a spectral map. In Red spectrum, Green spectrum and Blue spectrum boxes, you must browse to select spectrum files for converting a color bitmap into a spectral map.

Dimensions

In Dimensions group box, you must set the width and height of the converted xmp map in millimeters.

You can select the Respect ratio check box to keep ratio between width and height.