diff --git a/src/kiri/mode/fdm/init-menu.js b/src/kiri/mode/fdm/init-menu.js
index bb34b97f..73b93a1f 100644
--- a/src/kiri/mode/fdm/init-menu.js
+++ b/src/kiri/mode/fdm/init-menu.js
@@ -82,11 +82,12 @@ export function menu() {
     sliceDetectThin:     newSelect(LANG.ad_thin_s, { title: LANG.ad_thin_l, action: thinWallSave }, "thin"),
     outputAlternating:   newBoolean(LANG.ad_altr_s, onBooleanClick, {title:LANG.ad_altr_l}),
     sliceZInterleave:    newBoolean(LANG.ad_zint_s, onBooleanClick, {title:LANG.ad_zint_l, show:zIntShow}),
+    separator:           newBlank({ class:"set-sep", driven }),
+    sliceFillOverlap:    newInput(LANG.fi_over_s, {title:LANG.fi_over_l, convert:toFloat, bound:bound(0.0,2.0)}),
     _____:               newGroup(LANG.fi_menu, $('fdm-fill'), { modes:FDM, driven, hideable, separator, group:"fdm-fill" }),
     sliceFillType:       newSelect(LANG.fi_type, {trigger}, "infill"),
     sliceFillSparse:     newInput(LANG.fi_pcnt_s, {title:LANG.fi_pcnt_l, convert:toFloat, bound:bound(0.0,1.0), show:hasInfill}),
     sliceFillRepeat:     newInput(LANG.fi_rept_s, {title:LANG.fi_rept_l, convert:toInt,   bound:bound(1,10),    show:fillIsLinear}),
-    sliceFillOverlap:    newInput(LANG.fi_over_s, {title:LANG.fi_over_l, convert:toFloat, bound:bound(0.0,2.0), show:hasInfill}),
     separator:           newBlank({ class:"set-sep", driven }),
     sliceFillRate:       newInput(LANG.ou_feed_s, {title:LANG.ou_feed_l, convert:toInt,   bound:bound(0,500)}),
     sliceSolidRate:      newInput(LANG.ou_fini_s, {title:LANG.ou_fini_l, convert:toInt,   bound:bound(0,500)}),
@@ -178,7 +179,7 @@ export function menu() {
     outputCoastDist:     newInput(LANG.ad_scst_s, {title:LANG.ad_scst_l, convert:toFloat, bound:bound(0.0,10)}),
     zHopDistance:        newInput(LANG.ad_zhop_s, {title:LANG.ad_zhop_l, convert:toFloat, bound:bound(0,3.0)}),
     arcTolerance:        newInput(LANG.ad_arct_s, {title:LANG.ad_arct_l, convert:toFloat, bound:bound(0,1.0), show:() => { return isNotBelt() }}),
-    antiBacklash:        newInput(LANG.ad_abkl_s, {title:LANG.ad_abkl_l, convert:toInt,   bound:bound(0,3)}),
+    antiBacklash:        newInput(LANG.ad_abkl_s, {title:LANG.ad_abkl_l, convert:toFloat, bound:bound(0,3)}),
     outputLoops:         newInput(LANG.ag_loop_s, {title:LANG.ag_loop_l, convert:toInt,   bound:bound(-1,1000), show:isBelt}),
     outputPurgeTower:    newInput(LANG.ad_purg_s, {title:LANG.ad_purg_l, convert:toInt,   bound:bound(0,1000)}),
 
diff --git a/src/kiri/mode/fdm/post.js b/src/kiri/mode/fdm/post.js
index 655a569d..3ff454d7 100644
--- a/src/kiri/mode/fdm/post.js
+++ b/src/kiri/mode/fdm/post.js
@@ -247,7 +247,7 @@ function trace_noodle(noodle, noodleWidth, minR, midR, maxR, opt = {}) {
         showInset,
         showChainIntersect,
         minArea = midR * midR,
-        shellStep = 1 / 30, // diameter step as % of nozzle
+        shellStep = 1 / 100, // diameter step as % of nozzle
         lines = [],
         polys = [],
         remain = [],
diff --git a/src/kiri/mode/fdm/prepare.js b/src/kiri/mode/fdm/prepare.js
index d2bb8897..55808023 100644
--- a/src/kiri/mode/fdm/prepare.js
+++ b/src/kiri/mode/fdm/prepare.js
@@ -1130,12 +1130,13 @@ function slicePrintPath(print, slice, startPoint, offset, output, opt = {}) {
             if (np && np.distTo2D(new Point(trace[0].x, trace[0].y)) > retractDist) {
                 retract();
             }
+            let outputSpeed = trace.shell === 1 || trace.shell === 1.5 ? finishSpeed : printSpeed;
             for (let pt of trace) {
                 np = new Point(pt.x, pt.y, z);
                 if (pt === trace[0]) {
                     print.addOutput(preout, np, 0, moveSpeed);
                 } else {
-                    print.addOutput(preout, np, ((pt.r * 2) / nozzleSize) * shellMult, printSpeed);
+                    print.addOutput(preout, np, ((pt.r * 2) / nozzleSize) * shellMult, outputSpeed);
                 }
             }
         }
@@ -1237,10 +1238,10 @@ function slicePrintPath(print, slice, startPoint, offset, output, opt = {}) {
             start = 0,
             skip = false,
             lastIndex = -1,
-            raft = opt.raft || false,
+            raft = opt.raft ?? false,
             flow = opt.flow || 1,
-            near = opt.near || (antiBacklash ? false : true),
-            fast = opt.fast || false, // support infill only!
+            near = opt.near ?? (antiBacklash ? false : true),
+            fast = opt.fast ?? false, // support infill only!
             fill = (opt.fill >= 0 ? opt.fill : fillMult) * flow,
             thinDist = near ? thinWall : thinWall;