A 2D polygon: every used vertex whose projection falls inside it. Project your screen-space polygon to mesh-local coordinates with your camera first; axis picks the projection plane.
axis
Optional
The local plane projected onto. Defaults to "xy".
"xy"
Flat [x0, y0, x1, y1, ...] polygon corners in local coordinates.
[x0, y0, x1, y1, ...]
A 2D polygon: every used vertex whose projection falls inside it. Project your screen-space polygon to mesh-local coordinates with your camera first;
axispicks the projection plane.