# UTD Ray Contributions

A number of optional ray contribution parameters are available for the faceted UTD.

## Faceted UTD

- Direct field
- This option takes into account the direct rays.
- Edge and wedge diffraction
- This option takes into account the diffraction on edges and wedges.
- Surface reflection
- This option takes into account the rays reflected by the planar and curved surface.
- Creeping waves
- This option takes into account the creeping waves on curved surfaces.
- Corner and tip diffraction
- This option takes into account the diffraction at corners and tips.
- Higher-order effects
- This option allows for multiple reflections plus one edge/wedge diffraction at any position along the ray path to be computed. This option is only active if the Surface reflection and Edge and Wedge diffraction check boxes are selected and the Maximum number of ray interactions is larger than 1.

## UTD (Polygons and Cylinder)

- Direct and reflected
- This option takes into account both the direct rays and reflected rays.
- Double diffraction
- This option takes into account the double diffraction on edges and wedges and the combinations of reflections. Single diffraction rays are not included for this option.
- Edge and wedge diffractions
- This option takes into account the diffraction on edges and wedges. The ray may include an
arbitrary number of reflections, but only one diffraction. Note: The total number of interactions (number of reflections) plus one for the diffraction may not be larger than the value specified in the Maximum number of UTD ray interactions field.
- Creeping waves
- This option takes into account the creeping waves on a cylinder.
- Corner diffraction
- This option takes into account the corner diffraction.
- Cone tip diffraction
- This option takes into account the diffraction at the tip of the cone.