diff --git a/xs/src/admesh/connect.c b/xs/src/admesh/connect.c
index 56ebfa144..e9129d007 100644
--- a/xs/src/admesh/connect.c
+++ b/xs/src/admesh/connect.c
@@ -82,6 +82,16 @@ stl_check_facets_exact(stl_file *stl) {
 
   for(i = 0; i < stl->stats.number_of_facets; i++) {
     facet = stl->facet_start[i];
+    // Positive and negative zeros are possible in the floats, which are considered equal by the FP unit.
+    // When using a memcmp on raw floats, those numbers report to be different.
+    // Unify all +0 and -0 to +0 to make the floats equal under memcmp.
+    {
+      uint32_t *f = (uint32_t*)&facet;
+      for (int j = 0; j < 12; ++ j, ++ f) // 3x vertex + normal: 4x3 = 12 floats
+        if (*f == 0x80000000)
+            // Negative zero, switch to positive zero.
+            *f = 0;
+    }
 
     /* If any two of the three vertices are found to be exactally the same, call them degenerate and remove the facet. */
     if(   !memcmp(&facet.vertex[0], &facet.vertex[1],
@@ -278,6 +288,16 @@ stl_check_facets_nearby(stl_file *stl, float tolerance) {
 
   for(i = 0; i < stl->stats.number_of_facets; i++) {
     facet = stl->facet_start[i];
+    // Positive and negative zeros are possible in the floats, which are considered equal by the FP unit.
+    // When using a memcmp on raw floats, those numbers report to be different.
+    // Unify all +0 and -0 to +0 to make the floats equal under memcmp.
+    {
+      uint32_t *f = (uint32_t*)&facet;
+      for (int j = 0; j < 12; ++ j, ++ f) // 3x vertex + normal: 4x3 = 12 floats
+        if (*f == 0x80000000)
+            // Negative zero, switch to positive zero.
+            *f = 0;
+    }
     for(j = 0; j < 3; j++) {
       if(stl->neighbors_start[i].neighbor[j] == -1) {
         edge[j].facet_number = i;
diff --git a/xs/src/admesh/stl.h b/xs/src/admesh/stl.h
index 7871c0351..99fc61eed 100644
--- a/xs/src/admesh/stl.h
+++ b/xs/src/admesh/stl.h
@@ -197,6 +197,7 @@ extern void stl_rotate_z(stl_file *stl, float angle);
 extern void stl_mirror_xy(stl_file *stl);
 extern void stl_mirror_yz(stl_file *stl);
 extern void stl_mirror_xz(stl_file *stl);
+extern void stl_transform(stl_file *stl, float *trafo3x4);
 extern void stl_open_merge(stl_file *stl, char *file);
 extern void stl_invalidate_shared_vertices(stl_file *stl);
 extern void stl_generate_shared_vertices(stl_file *stl);
diff --git a/xs/src/admesh/stlinit.c b/xs/src/admesh/stlinit.c
index d7a436665..54f5b836c 100644
--- a/xs/src/admesh/stlinit.c
+++ b/xs/src/admesh/stlinit.c
@@ -318,29 +318,6 @@ stl_read(stl_file *stl, int first_facet, int first) {
       }
 #endif
 
-#if 1
-    {
-      // Positive and negative zeros are possible in the floats, which are considered equal by the FP unit.
-      // When using a memcmp on raw floats, those numbers report to be different.
-      // Unify all +0 and -0 to +0 to make the floats equal under memcmp.
-      uint32_t *f = (uint32_t*)&facet;
-      int j;
-      for (j = 0; j < 12; ++ j, ++ f) // 3x vertex + normal: 4x3 = 12 floats
-        if (*f == 0x80000000)
-          // Negative zero, switch to positive zero.
-          *f = 0;
-    }
-#else
-    {
-      // Due to the nature of the floating point numbers, close to zero values may be represented with singificantly higher precision 
-      // than the rest of the vertices. Round them to zero.
-      float *f = (float*)&facet;
-      for (int j = 0; j < 12; ++ j, ++ f) // 3x vertex + normal: 4x3 = 12 floats
-        if (*f > -1e-12f && *f < 1e-12f)
-          // Negative zero, switch to positive zero.
-          *f = 0;
-    }
-#endif
     /* Write the facet into memory. */
     memcpy(stl->facet_start+i, &facet, SIZEOF_STL_FACET);
     stl_facet_stats(stl, facet, first);
diff --git a/xs/src/admesh/util.c b/xs/src/admesh/util.c
index 0ee6b209c..a786240ad 100644
--- a/xs/src/admesh/util.c
+++ b/xs/src/admesh/util.c
@@ -185,6 +185,24 @@ void calculate_normals(stl_file *stl) {
   }
 }
 
+void stl_transform(stl_file *stl, float *trafo3x4) {
+  int i_face, i_vertex, i, j;
+  if (stl->error)
+    return;
+  for (i_face = 0; i_face < stl->stats.number_of_facets; ++ i_face) {
+    stl_vertex *vertices = stl->facet_start[i_face].vertex;
+    for (i_vertex = 0; i_vertex < 3; ++ i_vertex) {
+      stl_vertex &v_dst = vertices[i_vertex];
+      stl_vertex  v_src = v_dst;
+      v_dst.x = trafo3x4[0] * v_src.x + trafo3x4[1] * v_src.y + trafo3x4[2]  * v_src.z + trafo3x4[3];
+      v_dst.y = trafo3x4[4] * v_src.x + trafo3x4[5] * v_src.y + trafo3x4[6]  * v_src.z + trafo3x4[7];
+      v_dst.z = trafo3x4[8] * v_src.x + trafo3x4[9] * v_src.y + trafo3x4[10] * v_src.z + trafo3x4[11];
+    }
+  }
+  stl_get_size(stl);
+  calculate_normals(stl);
+}
+
 void
 stl_rotate_x(stl_file *stl, float angle) {
   int i;