This filter is found in the image window menu under
→ → .This filter creates a 3D effect by embossing an image (the card) and then mapping it to another image. Bump heigth depends on pixel luminosity and you can set light direction. See Emboss for more informations about embossing. You can bump map any type of image, unlike the Emboss filter.
This drop-down list allows you to select the image that will be used as a map for bumpmapping. This list contains images that are present on your screen when you launch the filter. Images opened after starting filter are not present in this list.
This option allows you to define the method that will be used when creating the map image:
Linear: bump heigth is a direct function of luminosity.
Sinusoidal: bump heigth is a sinusoidal function of luminosity.
Spheric: bump heigth is a spheric function of luminosity.
Bumpmapping tends to darken image. You can compensate this darkening by checking this option.
Bright pixels default to bumps and dark pixels to hollows. You can invert this effect by checking this option.
If you check this option, there will be no relief break if you use your image as a pattern for a web page: patterns will be placed side by side without any visible joins.
Azimut: This is about lighting according to the points of the compass (0 - 360). If you suppose South is at the top of your image, then East (0°) is on the left. Increasing value goes counter-clockwise.
Elevation: That's heighth from horizon (0°), in principle up to zenith (90°), but here up to the opposite horizon (180°).
With this slider, you can vary bump heigth and hollow depth. The higher the value, the higher the difference between both. Values vary from 0 to 100.
With this slider, you can adjust the map image position compared with the image, horizontally (X) and/or vertically (Y).
If your image has transparent areas, they will be treated like dark areas and will appear as hollows after bumpmapping. With this slider, you can reduce hollows as if sea level was raising. This hollows will disapear when sea level value reaches 255. If the Invert Bumpmap option is checked, transparent areas will be treated as bright areas, and then Sea Level slider will plane bumps down.
This slider controls the intensity of ambient light. With high values, shadows will fade and relief lessen.