Index: trunk/src/Makefile.dep
===================================================================
--- trunk/src/Makefile.dep	(revision 35968)
+++ trunk/src/Makefile.dep	(revision 35969)
@@ -704,7 +704,8 @@
  ../src_plugins/export_stl/exp_fmt_amf.c \
  ../src_plugins/export_stl/stl_models.c \
  ../src_plugins/export_stl/model_load_stl.c \
- ../src_plugins/export_stl/model_load_amf.c
+ ../src_plugins/export_stl/model_load_amf.c \
+ ../src_plugins/export_stl/verthash.c
 ../src_plugins/export_svg/svg.o: ../src_plugins/export_svg/svg.c \
  ../config.h conf_core.h globalconst.h board.h vtroutestyle.h attrib.h \
  global_typedefs.h layer.h obj_common.h flag.h data_parent.h \
Index: trunk/src_plugins/export_stl/export_stl.c
===================================================================
--- trunk/src_plugins/export_stl/export_stl.c	(revision 35968)
+++ trunk/src_plugins/export_stl/export_stl.c	(revision 35969)
@@ -342,6 +342,10 @@
 };
 RND_INLINE void v_transform(double dst[3], double src[3], double mx[16]);
 
+#include "verthash.c"
+
+static verthash_t verthash;
+
 #include "exp_fmt_stl.c"
 #include "exp_fmt_amf.c"
 #include "stl_models.c"
Index: trunk/src_plugins/export_stl/verthash.c
===================================================================
--- trunk/src_plugins/export_stl/verthash.c	(nonexistent)
+++ trunk/src_plugins/export_stl/verthash.c	(revision 35969)
@@ -0,0 +1,76 @@
+#include <genvector/vtl0.h>
+
+typedef struct {
+	rnd_coord_t x, y, z;
+} vertex_t;
+
+typedef vertex_t htvx_key_t;
+typedef long int htvx_value_t;
+#define HT(x) htvx_ ## x
+#include <genht/ht.h>
+#include <genht/ht.c>
+#undef HT
+
+
+typedef struct {
+	htvx_t vxhash;
+	vtl0_t triangles;
+	long next_id;
+} verthash_t;
+
+
+unsigned vxkeyhash(vertex_t key)
+{
+	return key.x ^ key.y ^ key.z;
+}
+
+int vxkeyeq(const vertex_t a, const vertex_t b)
+{
+	return (a.x == b.x) && (a.y == b.y) && (a.z == b.z);
+}
+
+static void verthash_init(verthash_t *vh)
+{
+	htvx_init(&vh->vxhash, vxkeyhash, vxkeyeq);
+	vtl0_init(&vh->triangles);
+	vh->next_id = 0;
+}
+
+static void verthash_uninit(verthash_t *vh)
+{
+	vtl0_uninit(&vh->triangles);
+	htvx_uninit(&vh->vxhash);
+}
+
+static long verthash_add_vertex(verthash_t *vh, rnd_coord_t x, rnd_coord_t y, rnd_coord_t z)
+{
+	long id;
+	vertex_t vx;
+	htvx_entry_t *e;
+	
+	vx.x = x; vx.y = y; vx.z = z;
+	e = htvx_getentry(&vh->vxhash, vx);
+	if (e != 0)
+		return e->value;
+
+	id = vh->next_id;
+	vh->next_id++;
+	htvx_set(&vh->vxhash, vx, id);
+	return id;
+}
+
+static void verthash_add_triangle(verthash_t *vh, long v1, long v2, long v3)
+{
+	vtl0_append(&vh->triangles, v1);
+	vtl0_append(&vh->triangles, v2);
+	vtl0_append(&vh->triangles, v3);
+}
+
+static void verthash_add_triangle_coord(verthash_t *vh, rnd_coord_t x1, rnd_coord_t y1, rnd_coord_t z1, rnd_coord_t x2, rnd_coord_t y2, rnd_coord_t z2, rnd_coord_t x3, rnd_coord_t y3, rnd_coord_t z3)
+{
+	long v1, v2, v3;
+	v1 = verthash_add_vertex(vh, x1, y1, z1);
+	v2 = verthash_add_vertex(vh, x2, y2, z2);
+	v3 = verthash_add_vertex(vh, x3, y3, z3);
+	verthash_add_triangle(vh, v1, v2, v3);
+}