Synopsis
		sfunif3 < surface.rsf > model.rsf x0= y0= z0= v00= dvdx= dvdy= dvdz= n1= d1= o1=0. layers=

Unless layers= is specified, velocity is a linear function of position inside
each layer.

Inspired by SU's unif2.

Parameters
		float d1= Sampling of the depth axis   floats dvdx= [ninf]   floats dvdy= [ninf]   floats dvdz= [ninf]   string layers= file with layer properties   int n1= Number of samples on the depth axis   float o1=0. Origin of the depth axis   floats v00= [ninf]   floats x0= [ninf]   floats y0= [ninf]   floats z0= [ninf]

Used In
		CWP          geo2006TimeShiftImagingCondition/flat   GALLERY          french/gazdag french/lowrank french/model french/oway french/stolt french/vc   JLU          gvdseisint/ocmodel txyapf/french   OSU          shalek/elastic3d   RSF          rsf/unif3   TCCS          decomp/frenchtri dlchan/label dlchan/testing dlchan/thin elas/french-dc oc3/french