For a Bitmap, you can set or modify the following parameters in the Bitmap Parameters rollout:
Bitmap: Click to select the bitmap using the standard file browser. Once you have selected the bitmap, its name appears on this button.
Reload: Reloads the bitmap file using the same name and path. This saves you having to use the file browser to reload the bitmap after you’ve updated it in your paint program.
Clicking reload for any instance of the map updates the map in all sample windows and in the scene.
Selects the method of pixel averaging used in antialiasing the bitmap. Summed area filtering yields generally superior results but requires much more memory. Pyramidal filtering is quite adequate for most purposes.
Determines which channels of the image are used by the various mapping types.
RGB Intensity: Uses the intensity of the red, green, and blue channels for mapping. The color of the pixels is ignored and only the value or luminance of the pixels is used. The colors are computed as gray values in the range between 0 (black) and 255 (white).
Alpha: Uses the intensity of the alpha channel for mapping.
The options in this area affect only maps for material components that display color; namely Ambient, Diffuse, Specular, Filter Color, Reflection, and Refraction.
RGB: (The default.) Displays the full color values of the pixels.
Alpha as Gray: Displays tones of gray, based on the various levels of the alpha channel are displayed in tones of gray.
The controls in the this area let you crop the bitmap or reduce its size for custom placement.
Croppiing a bitmap means to reduce it to a smaller rectangular area than it originally had. Cropping doesn’t change the scale of the bitmap.
Placing a bitmap lets you scale the size of the map and place it anywhere within its tile. Scaling does change the bitmap’s scale, but shows the entire bitmap.
The four values that specify the placement and size of the cropping or placement region are all animatable.
Cropping and placement settings affect the bitmap only as it’s used for this map and any instances of the map. They have no effect on the bitmap file itself.
Apply: Turn on to use the cropping or placements settings. Turn off to disable them.
View Image: Click to display a Virtual Frame Buffer that shows the bitmap surrounded by a region outline. The region outline has handles at its sides and corners. When cropping is on, dragging the handles changes the size of the crop area. You can also drag within the region area to move it. When placement is on, dragging the region area handles changes the scale of the bitmap, and dragging the image changes its location within the tile area.
The Virtual Frame Buffer dialog has U/V and W/H (width/height) spinners on its toolbar. These are another way to adjust the image’s (or crop area’s) location and size.
When Crop is the active option:
Crop: Makes cropping active.
Place: Makes placement active.
U/V: These spinners adjust the bitmap location.
W/H: These spinners (width and height) adjust the bitmap (or crop area) size.
Jitter Placement: When the checkbox is on, the size and position specified by the spinners or Virtual Frame Buffer is ignored, and 3DS MAX chooses a random size and tile position for the image. The Jitter Placement value specifies the amount of ramdom offset. When the value is zero, there is no random offset. The value can range from zero to 1.0. Default = 1.0.
Determines the source of the transparency information for bitmaps.
Image Alpha: Uses the image’s alpha channel (disabled if the image has no alpha channel).
RGB Intensity: Converts the colors in the bitmap to grayscale tonal values and uses them for transparency. Black is transparent and white is opaque.
None (opaque): Does not use transparency.
Premultiplied Alpha: Determines how alpha is treated in the bitmap. As a default, the checkbox is on, meaning premultiplied alpha is expected in the file. When turned off, the alpha is treated as non-premultiplied, and any RGB values are ignored.
If you apply an alpha image as, say, a Diffuse map, and it doesn’t decal correctly, it’s probably because the bitmap file contains non-premultiplied alpha, and the RGB values are maintained separately from the alpha values. To correct this, turn off the Premultiplied Alpha checkbox.
A virtual frame buffer appears, displaying the image. surrounded by a region outline. The region outline appears as a dashed line at the outer edges of the image, with handles on the sides and corners.
The reduced image “decals” on the sample sphere. The diffuse color is visible around the image.
This radio button is disabled if the bitmap does not have an alpha channel.
3DS MAX creates an alpha channel. Full-intensity areas of the image are opaque, zero-intensity areas are transparent, and intermediate colors become partially transparent.
3DS MAX ignores the bitmap's alpha channel, if present, and does not create a new one.