The cross-domain attention layer maintains the same
structure as the original self-attention layer and is integrated
before the cross-attention layer in each transformer block of
the UNet, as depicted in Figure 4. In the cross-domain at-
tention layer, the keys and values from the normal and color
image domains are combined and processed through atten-
tion operations. This design ensures that the generations of
color images and normal maps are closely correlated, thus
promoting geometric consistency between the two domains.

4.3. Textured Mesh Extraction
To extract explicit 3D geometry from 2D normal maps and
color images, we optimize a neural implicit signed distance
field (SDF) to amalgamate all 2D generated data. Unlike al-
ternative representations like meshes, SDF offers compact-
ness and differentiability, making them ideal for stable op-
timization.
Wonder3D