MedicalVisualization
Marching Quads Algorithm
← Line Based Iso-Contouring | ● | Marching Quads Cases →
For each cell the extracted line segment of the iso line for a particular iso value v, works by classifying each corner value s as below ($ s<v $) or above of the iso value ($ s \ge v $).
Each edge of the cell, that has one corner value classified as below and one classified as above (denoted usually by + and -) has an intersection with the iso line.
There are $2^4$ cases, many of which are symmetrical. There are three main principal cases:
- no line segment
- one line segment
- two line segments as part of a saddle point
The latter case is ambiguous, which can be resolved by interpolating the center point and classifying it as well.