O-Mapping is a phase in [[Forward Mapping]] for mapping a [[Bitmap Image]] to a 3D [[Triangular Mesh]]. This goes from the intermediate [[S-Mapping|S-Mapped]] surface to a more complex [[Triangular Mesh|Mesh]].
![[Pasted image 20251027164251.png|invert_S]]
There are 4 ways to O-Map:
- Reflected Ray
- Use the eye [[Vector]] to [[Reflection Transformations|Reflection]] from the object to $S$
- Object Normal
- Use the object's [[Normal Vector|Normal]] to $S$
- Object Centroid
- Use the intersection between the point and the center of the object to map to $S$
- Intermediate Surface Normal (ISM)
- Project $S$ onto the object using the normal vector from $S$.
Common combinations of [[S-Mapping]] and [[O-Mapping]] are:
- Plane / ISN - Good for planar objects
- Cylinder / ISN - Works for solids generated by [[Area of a Surface of Revolution|Revolution]]
While these work for roughly spherical shapes:
- Sphere / Centroid
- Box / Centroid
- Box / iSN
>[!example] Example: Cylinder / ISN
![[Screenshot 2025-10-27 at 4.51.21 PM.png|invert_S]]