Eyeon:Manual/Fusion 6/Bump

The Bump tool converts an image into a bump material. It handles greyscale images as a heightmap, or bumpmap images processing the RGB values directly. Check the notes for the naming conventions used in Fusion. Both the greyscale and bumpmap mode expects the color values to be in the range [0,1]. In some cases, if your image values are in the range [-1,1], you have to "compress" your bumpmaps or normalmaps in order to work correctly.

While the bump tool adds visual detail, it does not displace/modify the geometry or change the topology of the mesh. It is purely a lighting effect.

Input Port

Bump.Input (white): Receives the RGBA channels from an image output for the bump calculation

Controls Tab

This tab contains all parameters for the tool

The Source Image is a...

The bump information can be derived from different type of images. Use Heightmap if the image contains a greyscale information representing the surface structure. If the image represents the normal information of the surface, then use Bumpmap. While Heightmap offers options for calculating the normals, Bumpmap uses the RGB values directly and all other options (except the Material ID) are disabled.

Filter Size

The process of generating the bump information is basically a Custom Filter. This multibutton control sets the filter size.

Extract height information from...

Set the channel from where to extract the greyscale information from.

Clamp Normal.Z

Ask Stephen... It "clips" the lower values of blue channel in the resulting bump texture (max(slider,bluechannel))?

Filter Wrap Mode

Basically "wraps" the image at the borders, so the filter produces correct result when using seamless tileable textures.

Height Scale

Changes the contrast of the resulting values in the bump map. Increasing this value yields in a more visible bump map.

Bumpmap Texture Depth

Optionaly converts the resulting bump texture into the desired bit depth.

MaterialID

The Material ID for the resulting material. This value will be rendered into the MatID auxiliary channel if the accoring option is enabled in the renderer.

Notes

There is some confusion of terminology with bumpmapping depending which papers/books/people you are reading/talking to. This can cause confusion for artists. Here are Fusion conventions:

Heightmap

An greyscale image containing a height value per pixel

Bumpmap

An image containing normals stored in the RGB channels used for modifying the existing normals (usually given in tangent space)

Normalmap

An image containing normals stored in the RGB channels used for replacing the existing normals (usually given in tangent or object space)

Tips for Bump (edit)

If your geometry allows, use Displace3D with a blurred version of the heightmap. Combined with the bumpmap in the material, the siluette of the object looks more realistc.