diff --git a/Fonderie/crapulator.c b/Fonderie/crapulator.c
index d9ec1103..73703a46 100644
--- a/Fonderie/crapulator.c
+++ b/Fonderie/crapulator.c
@@ -197,7 +197,7 @@ switch (idFx) {
 		retval = insitu_filtre3x3(image, 1);
 		break;
 	case 20:
-		retval = octotree_classif(image, 0.5, 0);
+		retval = octotree_classif(image, 0.500, 0);
 		break;
 
 
diff --git a/Fonderie/sfx.c b/Fonderie/sfx.c
index 371e9216..d7aab102 100644
--- a/Fonderie/sfx.c
+++ b/Fonderie/sfx.c
@@ -7,6 +7,7 @@
 #include  <string.h>
 #include  <stdlib.h>
 #include  <malloc.h>
+#include  <math.h>
 
 #include  "../floatimg.h"
 
@@ -21,33 +22,87 @@ extern	int		verbosity;
 /* -------------------------------------------------------------- */
 /* nouveau du 27 decembre 2020, un soir de grand froid...         */
 
-int octotree_classif(FloatImg *pimg, int notused)
+int octotree_classif(FloatImg *pimg, float kdist, int notused)
 {
 int		foo;
-float		mm[6], means[4];
+float		mm[6], means[4],  delta[3];
+float		r, g, b, kr, kg, kb, dp, trig;
+int		idx, sz, n8, count;
+typedef struct {
+	float	x, y, z;
+	} ptc_t;
+ptc_t	ptc[8];
 
-fprintf(stderr, ">>> %s ( %p %d )\n", __func__, pimg, notused);
 
+fprintf(stderr, ">>> %s ( %p %f %d )\n", __func__,
+				pimg, kdist, notused);
+
+#if 0
 foo = fimg_meanvalues(pimg, means);
 if (foo) {
 	fprintf(stderr, "oups %d in meanvalues\n", foo);
 	return foo;
 	}
-fprintf(stderr, "means:  %11f  %11f  %11f\n", means[0], means[1], means[2]);
+fprintf(stderr, "means:  %11f  %11f  %11f\n",
+				means[0], means[1], means[2]);
+#endif
 
 foo = fimg_get_minmax_rgb(pimg, mm);
 if (foo) {
 	fprintf(stderr, "oups %d in get minmax\n", foo);
 	return foo;
 	}
-fimg_print_minmax(mm, __func__);
+if (verbosity) fimg_print_minmax(mm, "input pic");
 
 /*
- *		compute the height center points */
+ *		compute the 8 center points
+ */
+delta[0] = mm[1] - mm[0];	/* R */
+delta[1] = mm[3] - mm[2];	/* G */
+delta[2] = mm[5] - mm[4];	/* B */
+fprintf(stderr, "delta:  %11.3f  %11.3f  %11.3f\n",
+				delta[0], delta[1], delta[2]);
+for (idx=0; idx<8; idx++) {
+	kr = 0.25 * ((idx & 0x4) ? 1 : 3);
+	kg = 0.25 * ((idx & 0x2) ? 1 : 3);
+	kb = 0.25 * ((idx & 0x1) ? 1 : 3);
+	// fprintf(stderr, "%6d    %.2f %.2f %.2f\n", idx, kr, kg, kb);
+	ptc[idx].x = (delta[0] * kr) + mm[0];
+	ptc[idx].y = (delta[1] * kg) + mm[2];
+	ptc[idx].z = (delta[2] * kb) + mm[4];
+	fprintf(stderr, "%6d    %.3f   %.3f   %.3f\n", idx,
+			ptc[idx].x, ptc[idx].y, ptc[idx].z);
+	}
 
+sz = pimg->width * pimg->height;
+fprintf(stderr, "surface image %d\n", sz);
+trig = kdist * ((mm[1] + mm[3] + mm[5])/6.0);
+fprintf(stderr, "trig value %f\n", trig);
 
+count = 0;
 
-return -1;
+#define  X(a,b)		( ((a)-(b)) * ((a)-(b)) )
+for (idx=0; idx<sz; idx++) {
+
+	r = pimg->R[idx]; g = pimg->G[idx]; b = pimg->B[idx];
+	for (n8=0; n8<8; n8++) {
+		dp = sqrt(X(r,ptc[n8].x) + X(g,ptc[n8].y) + X(b,ptc[n8].z) );
+		if (dp < trig) {
+			pimg->R[idx] = ptc[n8].x;
+			pimg->G[idx] = ptc[n8].y;
+			pimg->B[idx] = ptc[n8].z;
+			count++;
+			break;
+			}
+		else	{
+			pimg->R[idx]=pimg->G[idx]=pimg->B[idx]=0.0;
+			}
+		}
+	}
+
+fprintf(stderr, "found %d pixels ok\n", count);
+
+return 0;
 }
 /* -------------------------------------------------------------- */
 /* nouveau du 19 decembre 2020, pour le grand ecran de da Scritch */