diff --git a/apps/tools/twndel/state.h b/apps/tools/twndel/state.h
index fbe224f..f24bdab 100644
--- a/apps/tools/twndel/state.h
+++ b/apps/tools/twndel/state.h
@@ -20,6 +20,10 @@
 
 #define CAMERA_ROTATION_SPEED 0.04f
 #define SELECTION_SPHERE_RADIUS 32
+/* should be an odd number */
+#define SNAP_LINES_SHOW 7
+#define SNAP_LINES_WIDTH 1.0f
+#define SNAP_LINES_COLOR ((Color){200,200,200,150})
 
 typedef struct Operation {
     enum {
diff --git a/apps/tools/twndel/tool.c b/apps/tools/twndel/tool.c
index 4c46f01..82b5050 100644
--- a/apps/tools/twndel/tool.c
+++ b/apps/tools/twndel/tool.c
@@ -242,6 +242,39 @@ static bool vector_plane_intersection(Vec3 o, Vec3 v, Vec3 p, Vec3 n, Vec3 *out)
 }
 
 
+static void show_snap_lines(Vec3 p) {
+    float step = 1.0f / ((float)POINTS_PER_METER / state.grid_snap_granularity);
+    int const lines_per_side = (SNAP_LINES_SHOW - 1) / 2;
+    for (int l = -lines_per_side; l <= lines_per_side; ++l) {
+        if (!state.axis_mask[0]) {
+            Vec3 c = vec3_add(p, vec3_scale((Vec3){1,0,0}, step * (float)l));
+            draw_line_3d(
+                vec3_add(c, vec3_scale((Vec3){0,0,1},  SNAP_LINES_WIDTH)),
+                vec3_add(c, vec3_scale((Vec3){0,0,1}, -SNAP_LINES_WIDTH)),
+                1,
+                SNAP_LINES_COLOR);
+        }
+        if (!state.axis_mask[1]) {
+            Vec3 axis = fabsf(vec3_dot(state.camera_direction, (Vec3){0,0,1})) >= 0.5f ? (Vec3){1,0,0} : (Vec3){0,0,1};
+            Vec3 c = vec3_add(p, vec3_scale((Vec3){0,1,0}, step * (float)l));
+            draw_line_3d(
+                vec3_add(c, vec3_scale(axis,  SNAP_LINES_WIDTH)),
+                vec3_add(c, vec3_scale(axis, -SNAP_LINES_WIDTH)),
+                1,
+                SNAP_LINES_COLOR);
+        }
+        if (!state.axis_mask[2]) {
+            Vec3 c = vec3_add(p, vec3_scale((Vec3){0,0,1}, step * (float)l));
+            draw_line_3d(
+                vec3_add(c, vec3_scale((Vec3){1,0,0},  SNAP_LINES_WIDTH)),
+                vec3_add(c, vec3_scale((Vec3){1,0,0}, -SNAP_LINES_WIDTH)),
+                1,
+                SNAP_LINES_COLOR);
+        }
+    }
+}
+
+
 static void process_operation_move_point(Operation *op) {
     /* finish dragging around */
     /* TODO: dont keep empty ops on stack? */
@@ -262,16 +295,15 @@ static void process_operation_move_point(Operation *op) {
     Vec3 p = point_to_vec3(op->data.move_point.object, op->data.move_point.point);
     bool point_moved = false;
 
-    /* TODO: show thresholds */
-    /* TODO: planes used should depend on looking angle */
-    /*       for example, editing from the side makes better use of x/z facing planes */
-
     /* figure out which planes are angled acutely against the viewing direction */
     bool y_closer_than_horizon = fabsf(vec3_dot(state.camera_direction, (Vec3){0,1,0})) >= 0.5f;
 
     Vec3 plane_normal_x = y_closer_than_horizon ? (Vec3){0,1,0} : (Vec3){0,0,1};
     Vec3 plane_normal_z = y_closer_than_horizon ? (Vec3){0,1,0} : (Vec3){1,0,0};
 
+    /* show snapping in lines */
+    show_snap_lines(p);
+
     Vec3 s;
     if (!state.axis_mask[0]) {
         if (vector_plane_intersection(cam.position, cam.direction, p, plane_normal_x, &s)) {