diff --git a/src/geo/slicer.js b/src/geo/slicer.js
index 3ce82017..88e575c5 100644
--- a/src/geo/slicer.js
+++ b/src/geo/slicer.js
@@ -565,6 +565,11 @@ export function sliceConnect(input, z, opt = {}) {
 
     // emit a polygon if it can be cleaned and still have 2 or more points
     function emit(poly) {
+        let gap = poly.first().distTo2D(poly.last());
+        if (opt.strict && gap > bridgeMax) {
+            if (debug) console.log('drop', gap, poly);
+            return;
+        }
         emitted += poly.length;
         if (!opt.dirty) poly = poly.clean();
         if (poly.length > 2 || true) output.push(poly);
diff --git a/src/kiri/mode/fdm/slice.js b/src/kiri/mode/fdm/slice.js
index b6505093..2a99d529 100644
--- a/src/kiri/mode/fdm/slice.js
+++ b/src/kiri/mode/fdm/slice.js
@@ -222,6 +222,7 @@ export function fdm_slice(settings, widget, onupdate, ondone) {
     }
 
     slice(points, {
+        strict: true,
         debug: process.xray,
         xray: process.xray,
         zMin: bounds.min.z,
diff --git a/src/kiri/mode/laser/driver.js b/src/kiri/mode/laser/driver.js
index c097bfa4..daedf895 100644
--- a/src/kiri/mode/laser/driver.js
+++ b/src/kiri/mode/laser/driver.js
@@ -191,6 +191,7 @@ function laser_slice(settings, widget, onupdate, ondone) {
     let indices = [];
 
     slicer.slice(points, {
+        strict: true,
         zMin: bounds.min.z,
         zMax: bounds.max.z,
         zGen(zopt) {