Polygon rendering parameters

Polygon rendering parameters

Arguments

cull_backfaces

Logical indicating whether to remove back-facing polygons from rendering. This is primarily for performance optimization but may be useful for aesthetic reasons in some situations. Backfaces are determined using screen-space winding order after 3D transformation. Defaults vary by geometry type: FALSE for open surface-type geometries, TRUE for solid objects (hulls, voxels, etc. where backfaces are generally hidden unless frontfaces are transparent or explicitly disabled).

sort_method

Character indicating algorithm used to determine the order in which polygons are rendered.

• "painter": Polygons are sorted by the mean depth (distance from viewer after rotation) of their vertices. This is fast, but can give incorrect results in certain cases.

• "pairwise": A more intensive sorting algorithm that compares every pair of polygons in 3D to determine which face should be rendered behind the other; slower but more accurate.

• "auto": The default. Uses pairwise if polygon data has less than 500 rows and painter otherwise.

scale_depth

Logical indicating whether polygon linewidths should be scaled to make closer lines wider and farther lines narrower. Default is TRUE. Scaling is based on the mean depth of a polygon.

force_convex

Logical indicating whether to remove polygon vertices that are not part of the convex hull. Default value varies by geom. Specifying TRUE can help reduce artifacts in surfaces that have polygon tiles that wrap over a visible horizon. For prism-type geoms like pillars and voxels, FALSE is safe because polygons fill always be convex.