--- ray/src/rt/aniso.c	1992/04/20 09:25:47	2.13
+++ ray/src/rt/aniso.c	1992/04/22 09:05:27	2.14
@@ -34,6 +34,8 @@ extern double  specjitter;		/* specular sampling jitte
  *  8  red 	grn	blu	rspec	u-rough	v-rough	trans	tspec
  */
 
+#define  BSPEC(m)	(6.0)		/* specularity parameter b */
+
 				/* specularity flags */
 #define  SP_REFL	01		/* has reflected specular component */
 #define  SP_TRAN	02		/* has transmitted specular */
@@ -196,6 +198,11 @@ register RAY  *r;
 		else
 			setcolor(nd.scolor, 1.0, 1.0, 1.0);
 		scalecolor(nd.scolor, nd.rspec);
+						/* improved model */
+		dtmp = exp(-BSPEC(m)*nd.pdot);
+		for (i = 0; i < 3; i++)
+			colval(nd.scolor,i) += (1.0-colval(nd.scolor,i))*dtmp;
+		nd.rspec += (1.0-nd.rspec)*dtmp;
 						/* check threshold */
 		if (specthresh > FTINY &&
 				(specthresh >= 1.-FTINY ||