Table of Contents

This page provides information about the Bitmap node in V-Ray for Blender. 


Overview


The Bitmap node can be used to load high dynamic range images (HDRI) or other file formats. Once you attach your desired file, its name is displayed above the node.


UI Path: ||V-Ray Node Editor|| > Shader > Add > Textures V-Ray Bitmap



Node Input Sockets


MappingAllows a UVW Mapping, or a UVW Randomizer node to be connected to determine the mapping of the ramp.



Bitmap Parameters



Image – Specifies the file name, from which the bitmap is loaded. Currently supported formats are HDR, EXR, PNG, BMP, TGA, SGI, JPG, PIC, TIF, PSD, VRIMG. Image file lists in the form of IFL files are also supported. Once a file is added, you are allowed to save the data or to unlink the data ().

Filter – Specifies the V-Ray internal texture filtering method. Possible values are:

Nearest The nearest texel from the map is taken without any interpolation. 
No filtering
– No filter is applied.
Mip-map filtering – Applies a Mip-map filter.
Summed are table filtering – Pyramidal Mip-map filtering is used to compute the texture color. Can be blurry for textures seen at grazing angles. 
Elliptical filtering – High-quality anisotropic MIP-map texture filtering that reduces blurring and aliasing artifacts.
Sharp mip-map filtering – Sharper but slower method in comparison to the Mip-map.

InterpolationDetermines how the image is interpolated from the pixel values. Possible values are:

Bilinear – Image values are interpolated from four pixels in the bitmap. This is the fastest interpolation method, but the result is not continuous (non-smooth) and may produce artifacts when the map is used for displacement or bump mapping.
Bicubic – Image values are interpolated from sixteen pixels in the bitmap. This is the slowest method, but the results are smooth without too much blur.
Biquadratic – Image values are interpolated from nine pixels in the bitmap. This method is faster than the Bicubic interpolation but may smooth the image too much. 
3dsMax auto – Interpolation type is chosen automatically, depending on the bitmap format to match the behavior of the standard texture. For HDR and EXR images, the interpolation is Bilinear, and for all other formats - Bicubic.

Filter Blur – Additional multiplier that controls filter blurring, especially useful with the mapping source feature. The higher the value, the more blurred the texture renders and the less render time it takes, and vice versa. A value of 0.01 means no filtering but leads to increased render times.

Transfer Function – Specifies the color space for the loaded image file. You can manually modify the value.

Linear – No correction is applied.
Gamma corrected  – The color space is controlled through the Gamma parameter.
sRGB  – The loaded image is considered in sRGB color space.
Auto – Automatically determines the color transfer function. If a bitmap file name contains the string "_srgb" the transfer function is sRGB. If a bitmap file name contains the strings "_lin_srgb" or "raw", no correction is applied. For bitmap files with 8 bits per color component and 3 or 4 color components (like png, jpg, and others), the transfer function is sRGB. In all other cases, no correction is applied.

Gamma – A gamma–correction value for the image. For example, if the bitmap was saved to disk with a 2.2 gamma correction, you need to enter 0.4545 to remove that correction for the rendering.

Color Space – Allows manual overriding of the RGB primaries of the bitmap.

Raw – No transformation is applied to R|G|B colors. This option is suitable for normal maps.
sRGB – The loaded image is considered in sRGB color space.
ACEScg – The loaded image is considered in ACEScg color space.

Allow Negative Colors – If disabled, negative colors are clamped. Enable to allow negative colors.



Color Parameters


Color Mult – Specifies a multiplier for the imported image file.

Color Offset –  Adjusts the correction of color offset RGB.

Invert Color – Inverts the colors of the Bitmap.



Alpha


Alpha Source – Specifies what the alpha source is:

Bitmap alpha – The alpha channel is drawn from the texture.
Color intensity/luminance – Alpha is generated from pixel intensity.
Force opaque – The Alpha channel is fully opaque.

Alpha Mult – Specifies a multiplier for the texture alpha.

Alpha Offset – Specifies an additional offset for the texture alpha.

Invert Alpha – When enabled and Invert from Color Tweaks is also on, the resulting texture alpha is inverted as well.



Mapping


Placement – Specifies the way the valid portion of the texture is applied:

Full– Uses the full valid portion of the texture.
Crop – Crop the texture or reduce its size for custom placement. Cropping a texture means reducing it to a smaller rectangular area than it originally had. Cropping doesn't change the scale of the texture.
Place – Scale the map and place it anywhere within its tile. Placing can change the texture's scale but shows the entire texture. 

Tilling – Specifies the way the texture 'tiles' or repeats along the surface of the object:

No tiling – No tilling is applied.
Tile in UV – Tiling is applied in bot the U and V axes.
Tile in U – Horizontal tiling is applied.
Tile in V – Vertical tiling is applied.
Tile in UV - No Filter – This mode tiles the texture in both the U and V axes, but no texture filtering is applied. Texture filtering blurs the bitmap, hiding imperfections and reducing render time.

Tile U / V Adjusts the texture location - specifies the location of the top left corner of the image. Only available for the Place placement.

Jitter – Determines the amount of randomization of the texture placement. Only available for the Place placement.



UV Noise


UV Noise On – Enables the UV noise.

UV Noise Amount –  Specifies the UV noise amount.

UV Noise Levels – Specifies the UV noise iterations.

UV Noise Size – Specifies the UV noise size.

Animate UV Noise – When enabled, the noise is animated.

UV Noise Phase – Specifies the UV noise phase.


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