Synopsis
		vpvr3d > out.rsf > plot.vpl what= start=0. end=360. bottom=-90. top=90. order=n maxlevel=5 coslimit=25. xmin=-100. ymin=-100. zmin=-100. xmax=100. ymax=100. zmax=100. or=n skip=-1 xxmin=-100. yymin=-100. zzmin=-100. xxmax=100. yymax=100. zzmax=100. inc=4 inc2=iinc which=y norm=1. sing=

Parameters
		float bottom=-90. latitude start   float coslimit=25. aximum deviation in particle motion angle   float end=360. longitude end   int inc=4 density of gridding (How many tiles to cover 90 degree of longitude in initial tiling.)   int inc2=iinc tiles bigger than 90 deg / iinc2 in any dimension will be subdivided to fit   int maxlevel=5 maximum number of re-subdivisions   float norm=1. amount to divide everything by   bool or=n [y/n] modifier: if or=y ORs instead of ANDS the clips.   bool order=n [y/n] try to swap around the surfaces to make them continuous   string sing= Log file   int skip=-1 modifier: skip=-1 don't clip this surface (-1 for none skipped) 0 = fastest 1 = intermediate 2 = slowest 3 = red (SH) 4 = green (SV) 5 = blue (P)   float start=0. longitude start   float top=90. latitude end   ints what= [3]   bool which=y [y/n] if y, plot impulse response; if n, plot slowness surface   float xmax=100.   float xmin=-100.   float xxmax=100.   float xxmin=-100.   float ymax=100.   float ymin=-100.   float yymax=100.   float yymin=-100.   float zmax=100.   float zmin=-100.   float zzmax=100.   float zzmin=-100.