ray_volume (boolean, default: off) If true then OpenGL rendered volumes will be blended into ray traced images. No real volume ray tracing implemented yet.

volume_bit_depth (integer, default: 16) Number of bits used per RGB channel for representing color (in 1.7.2: only valid values are 16 and 32).

volume_data_range (float, default: 5.0) Number of standard deviations above and below the mean around which color ramps should be colored.

volume_layers (integer, default: 256) Number of layers used to draw the volumes on screen. Drawing fewer layers increases real-time rendering speed; more layers reduces rendering speed (but increases color intensity in versions < 1.7.2).

volume_mode (integer, default: 1) volume rendering technique, 1: pre-integrated, 0: post-classified (New in PyMOL 1.7.2)