TRIRAY - dynamic RAY tracing for a TRIangulated sloth model		

  triray <modelfile >rayends [optional parameters]			

 Optional Parameters:							
 xs=(max-min)/2 x coordinate of source (default is halfway across model)
 zs=min	 z coordinate of source (default is at top of model)	
 nangle=101	number of takeoff angles				
 fangle=-45	first takeoff angle (in degrees)			
 langle=45	last takeoff angle (in degrees)				
 rayfile=	file of ray x,z coordinates of ray-edge intersections	
 nxz=101	number of (x,z) in optional rayfile (see notes below)	
 wavefile=	file of ray x,z coordinates uniformly sampled in time	
 nt=101	number of (x,z) in optional wavefile (see notes below)	
 infofile=	ASCII-file to store useful information 		
 fresnelfile=  used if you want to plot the fresnel volumes.		
		default is <fresnelfile.bin> 				
 outparfile=	contains parameters for the plotting software.		
		default is <outpar> 					
 krecord=	if specified, only rays incident at interface with index
		krecord are displayed and stored			
 prim=	   =1, only single-reflected rays are plotted			
		=0, only direct hits are displayed  			
 ffreq=-1	FresnelVolume frequency 				
 refseq=1,0,0  index of reflector followed by sequence of reflection (1)
		transmission(0) or ray stops(-1).			
		The default rayend is at the model boundary.		
		NOTE:refseq must be defined for each reflector		
 NOTES:								
 The rayends file contains ray parameters for the locations at which	
 the rays terminate.  							

 The rayfile is useful for making plots of ray paths.			
 nxz should be larger than twice the number of triangles intersected	
 by the rays.								

 The wavefile is useful for making plots of wavefronts.		
 The time sampling interval in the wavefile is tmax/(nt-1),		
 where tmax is the maximum time for all rays.				

 The infofile is useful for collecting information along the		
 individual rays. The fresnelfile contains data used to plot 		
 the Fresnel volumes. The outparfile stores information used 		
 for the plotting software.						



 AUTHOR:  Dave Hale, Colorado School of Mines, 02/16/91
 MODIFIED:  Andreas Rueger, Colorado School of Mines, 08/12/93
	Modifications include: functions writeFresnel, checkIfSourceIsOnEdge;
		options refseq=, krecord=, prim=, infofile=;
		computation of reflection/transmission losses, attenuation.