User Manual

Using a Height Map
A height map is an image where the value of a pixel represents the height. It is possible to
select which color channel is used for bump creation. White means high and black means low;
however, it is not the value of a pixel in the height map that determines the bumpiness, but
rather how the value changes in the neighborhood of a pixel.
Using a Bump Map
A bump map is an image containing normals stored in the RGB channels.
TIP: Normals are generated by 3D modeling and animation software as a way to trick
the eye into seeing smooth surfaces, even though the geometry used to create the
models uses only triangles to build the objects.
Normals are 3 float values (nx, ny, nz) whose components are in the range [–1, +1]. Because you
can store only positive values in Fusion’s integer images, the normals are packed from the
range [–1, +1] to the range [0, 1] by multiplying by 0.5 and adding 0.5. You can use Brightness
Contrast or a Custom node to do the unpacking.
If you were to connect a bump map directly to the bump map input of a material, it will result in
incorrect lighting. Fusion prevents you from doing this, however, because Fusion uses a
different coordinate system for doing the lighting calculation. You first must use a BumpMap
that expects a packed bump map or height map and will do the conversion of the bump map to
work correctly.
If your bump mapping doesn’t appear correct, here are a few things to look for:
 Make sure you have the nodes connected correctly. The height/bump map should
connect into a BumpMap and then, in turn, should connect into the bump map input on
a material.
 Change the precision of the height map to get less banding in the normals. For low
frequency images, float32 may be needed.
 Adjust the Height scale on the BumpMap. This scales the overall effect of the bump
map.
 Make sure you set the type to HeightMap or BumpMap to match the image input.
Fusion cannot detect which type of image you have.
 Check to ensure High Quality is on (right-click in the transport controls bar and choose
High Quality from the contextual menu). Some nodes like Text+ produce an anti-aliased
version in High Quality mode that will substantially improve bump map quality.
 If you are using an imported normal map image, make sure it is packed [0–1] in RGB and
that it is in tangent space. The packing can be done in Fusion, but the conversion to
tangent space cannot.
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