Bump Generator

 
 
 

| Texture | Bump Filtering | Advanced | Render Tree Usage

Category: Bump

Shader Family: Texture

Output: Vector

Uses an image file to create a bump map. This shader can be connected to any bump parameter in the render tree. You can define any image to use as a bump, use its alpha, as well as control the bump factor, the bump step, and the normals to use.

By default, the Bump Map Generator is loaded with the noicon_.pic image clip.

Name

The shader's name. Enter any name you like, or leave the default.

Texture

Texture Image

Defines an image clip to use. Click Edit to open a property page for the image clip being presently used. To retrieve a new clip, click New and indicate whether you wish to create a new clip or create one from a source.

Image View Window

Displays the selected image. You can right-click on the image to access the Image Clip Property Editor. If the image is a sequence, use the playback controls to play the sequence image.

Texture Space

Selects the texture projection to use. See Specifying a Texture Projection [Texturing].

Bump Mapping

Enable Bump

Switches on the bump mapping parameters.

Use Alpha

Uses the texture's alpha channel to achieve a bump map.

Clamp

Clamps the bump map to the area defined by the associated texture projection.

Factor

Defines how "bumpy" the bump map will be. A negative value inverts the bump inward; a positive bump map factor bumps outward.

Step

Controls the U, V, and Z steps of a bump map. Use this parameter to "smooth" bumps or make them more jagged.

Projection Method for Bump Basis Computation

When you apply a bumpmap to an object, discontinuities in the object's UV coordinates can cause artifacts in the rendered object. These options allow you to specify a second projection, with its own set of UV coordinates, that is used only for the bumpmap computation.

Enable

Activates the second, bumpmap-only projection.

Texture Projection

Specifies the type of projection to use. Choose one of the following:

  • Explicit UV: for deformed surfaces (shape/envelope): Uses an explicit texture projection, as defined by the second texture projection drop-down list below.

    You should use this type of projection on objects that are deformed by shape, envelope, and so on, because it properly maintains the "flow" of the bump map across the object's surface. If you use an implicit projection to control the bumpmap, the bumpmap may appear to swim as the object deforms.

  • Implicit UV: NURBS only: Uses an implicit UV type projection to compute the bumpmap. Because the projection is implicit, the UV coordinates are calculated at render time, and not added to the object as they would be with an explicit projection. This projection type only works for NURBS objects.

    You should only use implicit projections to compute bumpmaps on static objects with no deformations. Deformed objects require an explicit projection to maintain the bumpmap's "flow" as the object deforms.

  • Implicit Planar (XY/XZ/YZ)/ Spherical/ Cylindrical/ Lollipop: Use an implicit projection of the specified type to compute the bumpmap. Because the projection is implicit, the UV coordinates are calculated at render time, and not added to the object as they would be with an explicit projection.

    You should only use implicit projections to compute bumpmaps on static objects with no deformations. Deformed objects require an explicit projection to maintain the bumpmap's "flow" as the object deforms.

Texture Projection

Selects the texture projection to use. See Specifying a Texture Projection [Texturing].

Normal

Base Normal

Relative to Current: Uses the object's normal to compute the bump map.

Relative to Input: Uses a custom (user-defined) normal to compute the bump map.

Input Normal

Defines a custom normal direction. The three sliders correspond to the object's UVW coordinates and control how the texture's UV space corresponds to the surface of the object.

Bump Filtering

This type of filtering is used for high-detail textures that will be moving near to far from the camera, or vice versa. Use this filtering as a less memory-hungry alternative to increasing anti-aliasing on a bumpmapped texture. Elliptical filtering projects a circle (from the camera's pixel) on to the object's surface. Usually, the circle will be elliptical so that all the pixels within the projected circle will be looked up and computed when a color value is returned for all the pixels in the circle.

Enable

Enables the elliptical filtering options.

Maximum Eccentricity

Defines the eccentricity of the ellipse. The higher the value, the more pronounced the ellipse will be. This parameter defines the space between the ellipse's radii.

Maximum Pixels for Minimum Radius

Defines the maximum number of texture pixels for the minor radius of the ellipse.

Disc Radius

This value is used in the computation of screen-to-texture-space information. If artifacts appear when on objects with highly curved surfaces, use a value between 0 and 0.3.

Bilinear Interpolation

When enabled, magnified areas will be interpolated bilinearly, thus rendering these areas blurrier when seen close up as opposed to the common blocky look.

Advanced

Repeats

Texture Repeats

Contains the repetition factor in X,Y, and Z. A value of 2, for example, shrinks the texture so that it fits twice in a [0..1] interval.

Alternate U, V, Z

Specifies whether every other copy of the repetition should be reversed so that the successive copies of the texture are alternated.

Wrapping U, V, Z

Maps the texture space into a range of [0..1] so that values outside 0..1 are remapped to 0..1. E.g.: 1.76 is remapped to 0.76.

This parameter behaves differently when the above parameter is on, since it takes into account the texture alternation in its repeats.

UV Remap

Minimum, Maximum

Determines the remapping of the texture image. For a 2D image, only X and Y are used.

Render Tree Usage

This shader is most often connected to the material node or surface shader. Both of these nodes have a vector (yellow) Bump Map input. Using this shader is a good way to apply a bump map to an object without affecting the surface (color) of the object. You could further alter the effect by connecting a Texture Space Generator and/or Texture Space Controller to the Normal input of the shader.