--- ray/src/common/bsdf_m.c	2021/03/27 16:40:46	3.40
+++ ray/src/common/bsdf_m.c	2021/12/07 23:49:50	3.43
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: bsdf_m.c,v 3.40 2021/03/27 16:40:46 greg Exp $";
+static const char RCSid[] = "$Id: bsdf_m.c,v 3.43 2021/12/07 23:49:50 greg Exp $";
 #endif
 /*
  *  bsdf_m.c
@@ -709,18 +709,21 @@ SDloadMtx(SDData *sd, ezxml_t wtl)
 					/* separate diffuse components */
 	sd->rf = extract_diffuse(&sd->rLambFront, sd->rf);
 	sd->rb = extract_diffuse(&sd->rLambBack, sd->rb);
-	if (sd->tb != NULL)
-		sd->tb = extract_diffuse(&sd->tLamb, sd->tb);
-	if (sd->tf != NULL)
-		sd->tf = extract_diffuse(&sd->tLamb, sd->tf);
+	sd->tf = extract_diffuse(&sd->tLambFront, sd->tf);
+	if (sd->tb != NULL) {
+		sd->tb = extract_diffuse(&sd->tLambBack, sd->tb);
+		if (sd->tf == NULL)
+			sd->tLambFront = sd->tLambBack;
+	} else if (sd->tf != NULL)
+		sd->tLambBack = sd->tLambFront;
 					/* return success */
 	return SDEnone;
 }
 
 /* Get Matrix BSDF value */
 static int
-SDgetMtxBSDF(float coef[SDmaxCh], const FVECT outVec,
-				const FVECT inVec, SDComponent *sdc)
+SDgetMtxBSDF(float coef[SDmaxCh], const FVECT inVec,
+				const FVECT outVec, SDComponent *sdc)
 {
 	const SDMat	*dp;
 	int		i_ndx, o_ndx;