diff --git a/release.md b/release.md
index c5183ec9..bd194977 100644
--- a/release.md
+++ b/release.md
@@ -5,6 +5,7 @@ Full docs @ https://docs.grid.space/projects/kiri-moto
 
 # Release 3.6
 
+* allow FDM mixing of automatic and manual / detected supports
 * improve CAM animation speeds using shared array buffers
 * improve CAM render quality using solids instead of lines
 * add CAM leveling part offset parameters for XY and Z
diff --git a/src/kiri-mode/fdm/client.js b/src/kiri-mode/fdm/client.js
index 3c4fdb88..e229202c 100644
--- a/src/kiri-mode/fdm/client.js
+++ b/src/kiri-mode/fdm/client.js
@@ -130,23 +130,6 @@ FDM.init = function(kiri, api) {
           }
     }
 
-    api.event.on("boolean.click", func.updateSupportButtons = () => {
-        if (!isFdmMode) {
-            return;
-        }
-        for (let btn of [
-            ui.ssaGen,
-            ui.ssmAdd,
-            ui.ssmDun,
-            ui.ssmClr
-        ]) {
-            btn.disabled = ui.sliceSupportEnable.checked;
-        }
-        if (ui.sliceSupportEnable.checked) {
-            func.sclear();
-        }
-    });
-
     api.event.on("function.animate", (mode) => {
         if (!isFdmMode) {
             return;
@@ -205,7 +188,6 @@ FDM.init = function(kiri, api) {
     });
     api.event.on("settings.saved", (settings) => {
         updateRanges(settings.process.ranges);
-        func.updateSupportButtons();
         // let ranges = settings.process.ranges;
         // ui.rangeGroup.style.display = isFdmMode && ranges && ranges.length ? 'flex' : 'none';
     });
diff --git a/src/kiri-mode/fdm/prepare.js b/src/kiri-mode/fdm/prepare.js
index 757556f0..f4a63580 100644
--- a/src/kiri-mode/fdm/prepare.js
+++ b/src/kiri-mode/fdm/prepare.js
@@ -35,7 +35,7 @@ FDM.prepare = function(widgets, settings, update) {
     widgets = widgets.filter(w => !w.track.ignore && !w.meta.disabled);
 
     let { device, process, controller, bounds, mode } = settings,
-        { sliceHeight, firstSliceHeight, firstLayerRate } = process,
+        { sliceHeight, firstSliceHeight, firstLayerRate, sliceSupportOutline } = process,
         { outputSeekrate, outputDraftShield, outputPurgeTower } = process,
         { bedWidth, bedDepth, filamentSource } = device,
         { lineType, danger } = controller,
@@ -1358,7 +1358,9 @@ function slicePrintPath(print, slice, startPoint, offset, output, opt = {}) {
             print.setType('support');
             // support polygon
             next.setZ(z);
-            outputTraces([next].appendAll(next.inner || []));
+            if (sliceSupportOutline !== false) {
+                outputTraces([next].appendAll(next.inner || []));
+            }
             if (next.fill) {
                 next.fill.forEach(p => { p.z = z });
                 outputFills(next.fill, {fast: true});
diff --git a/src/kiri-mode/fdm/slice.js b/src/kiri-mode/fdm/slice.js
index b13c9fd7..a1240dd1 100644
--- a/src/kiri-mode/fdm/slice.js
+++ b/src/kiri-mode/fdm/slice.js
@@ -127,7 +127,8 @@ FDM.slice = function(settings, widget, onupdate, ondone) {
     // allow overriding support fill auto angle algorithm
     // also causes support fill to be aligned on start boundaries
     // best with angles that are a multiple of 90 degrees
-    if (process.sliceSupportFill !== undefined) {
+    if (process.sliceSupportFill >= 0) {
+        // yes, an ugly hack to allow it to pass through old code paths
         process.sliceSupportFill += 1000;
     }
 
@@ -414,8 +415,15 @@ FDM.slice = function(settings, widget, onupdate, ondone) {
                         if (Math.abs(Math.abs(pslice.z - slice.z) - gap) > 0.1) {
                             continue;
                         }
+                        let clipto = pslice.clips;
+                        if (pslice.supportOutline) {
+                            // merge support outlines into slice clips which
+                            // should only happen when automatic and manual
+                            // supports are used together
+                            clipto.appendAll(pslice.supportOutline);
+                        }
                         let ntops = [];
-                        POLY.subtract(tops, pslice.clips, ntops, null, slice.z, 0);
+                        POLY.subtract(tops, clipto, ntops, null, slice.z, 0);
                         tops = ntops;
                     }
                     // trim to group's shadow if not in belt mode
@@ -724,22 +732,17 @@ FDM.slice = function(settings, widget, onupdate, ondone) {
                 let density = params.sliceSupportDensity;
                 if (density)
                 for (let top of slice.tops) {
+                    let offset = [];
                     if (!outline) {
-                        let offset = top.shells;
-                        fillSupportPolys({
-                            promises, polys: offset, lineWidth, density, z: slice.z, isBelt,
-                            angle: process.sliceSupportFill
-                        });
-                        resolve.push({top, offset});
+                        POLY.expand(top.shells || [], lineWidth, slice.z, offset);
                     } else {
-                        let offset = [];
                         POLY.expand(top.shells || [], -lineWidth/4, slice.z, offset);
-                        fillSupportPolys({
-                            promises, polys: offset, lineWidth, density, z: slice.z, isBelt,
-                            angle: process.sliceSupportFill
-                        });
-                        resolve.push({top, offset});
                     }
+                    fillSupportPolys({
+                        promises, polys: offset, lineWidth, density, z: slice.z, isBelt,
+                        angle: process.sliceSupportFill
+                    });
+                    resolve.push({top, offset});
                 }
             }, "infill");
             if (promises) {
@@ -748,35 +751,11 @@ FDM.slice = function(settings, widget, onupdate, ondone) {
                 });
             }
             for (let rec of resolve) {
+                let spacing = lineWidth * (1 / supportDensity);
                 let lines = rec.top.fill_lines = rec.offset.map(o => o.fill).flat().filter(v => v);
-                // if copying simply's support type, eliminate shells
-                // and zig/zag lines connectd by shell segments
+                // if copying simply's support type, eliminate shells and zig/zag fill lines
                 if (!outline) {
-                    let newlines = [];
-                    let op2;
-                    let eo = 0;
-                    let idx = 1;
-                    for (let i=0; i<lines.length; i += 2) {
-                        let p1 = lines[i];
-                        let p2 = lines[i+1];
-                        p1.index = idx;
-                        p2.index = idx++;
-                        if (eo++ % 2 === 1) {
-                            let t = p1;
-                            p1 = p2;
-                            p2 = t;
-                        }
-                        if (op2) {
-                            let op1 = p1.clone();
-                            op1.index = op2.index;
-                            newlines.push(op2);
-                            newlines.push(op1);
-                        }
-                        newlines.push(p1);
-                        newlines.push(p2);
-                        op2 = p2.clone();
-                        op2.index = idx++;
-                    }
+                    let newlines = connect_lines(lines, spacing * 2);
                     rec.top.fill_lines = newlines;
                     rec.top.shells = [];
                 }
@@ -801,7 +780,8 @@ FDM.slice = function(settings, widget, onupdate, ondone) {
                 doSupportFill({
                     promises, slice, lineWidth, density: supportDensity,
                     minArea: process.sliceSupportArea, isBelt,
-                    angle: process.sliceSupportFill
+                    angle: process.sliceSupportFill,
+                    outline: process.sliceSupportOutline !== false
                 });
             }, "support");
             if (promises) {
@@ -832,6 +812,35 @@ FDM.slice = function(settings, widget, onupdate, ondone) {
 
 }
 
+function connect_lines(lines, maxd = Infinity) {
+    const newlines = [];
+    let op2;
+    let eo = 0;
+    let idx = 1;
+    for (let i=0; i<lines.length; i += 2) {
+        let p1 = lines[i];
+        let p2 = lines[i+1];
+        p1.index = idx;
+        p2.index = idx++;
+        if (eo++ % 2 === 1) {
+            let t = p1;
+            p1 = p2;
+            p2 = t;
+        }
+        if (op2 && p1.distTo2D(op2) <= maxd) {
+            let op1 = p1.clone();
+            op1.index = op2.index;
+            newlines.push(op2);
+            newlines.push(op1);
+        }
+        newlines.push(p1);
+        newlines.push(p2);
+        op2 = p2.clone();
+        op2.index = idx++;
+    }
+    return newlines;
+}
+
 function bound(v,min,max) {
     return Math.max(min,Math.min(max,v));
 }
@@ -847,7 +856,7 @@ function doRender(slice, isSynth, params, devel) {
             .addPolys(top.poly);
 
         output
-            .setLayer("shells", isSynth ? COLOR.support : COLOR.shell)
+            .setLayer(isSynth ? "support" : "shells", isSynth ? COLOR.support : COLOR.shell)
             .addPolys(top.shells || [], vopt({ offset, height, clean: true }));
 
         output
@@ -893,7 +902,7 @@ function doRender(slice, isSynth, params, devel) {
             .addAreas(slice.flats);
     }
 
-    if (slice.supports) output
+    if (slice.supports && params.sliceSupportOutline) output
         .setLayer("support", COLOR.support)
         .addPolys(slice.supports, vopt({ offset, height }));
 
@@ -902,6 +911,7 @@ function doRender(slice, isSynth, params, devel) {
             .setLayer("support", COLOR.support)
             .addLines(poly.fill, vopt({ offset, height }));
     });
+
     if (slice.xray) {
         const color = [ 0xff0000, 0x00aa00, 0x0000ff, 0xaaaa00, 0xff00ff, 0x0 ];
         if (slice.lines) {
@@ -1517,7 +1527,7 @@ async function doSupport(slice, proc, shadow, opt = {}) {
 }
 
 function doSupportFill(args) {
-    const { promises, slice, lineWidth, density, minArea, isBelt, angle } = args;
+    const { promises, slice, lineWidth, density, minArea, isBelt, angle, outline } = args;
     let supports = slice.supports,
         nsB = [],
         nsC = [],
@@ -1540,16 +1550,17 @@ function doSupportFill(args) {
 
     if (supports) {
         fillSupportPolys({
-            promises, polys: supports, lineWidth, density, z: slice.z, isBelt, angle
+            promises, polys: supports, lineWidth, density, z: slice.z, isBelt, angle, outline
         });
     }
 
     // re-assign new supports back to slice
+    slice.supportOutline = supports;
     slice.supports = supports;
 };
 
 function fillSupportPolys(args) {
-    const { promises, polys, lineWidth, density, z, isBelt, angle } = args;
+    const { promises, polys, lineWidth, density, z, isBelt, angle, outline } = args;
     // calculate fill density
     let spacing = lineWidth * (1 / density);
     polys.forEach(function (poly) {
@@ -1560,6 +1571,9 @@ function fillSupportPolys(args) {
         // do the fill
         if (inset && inset.length > 0) {
             doFillArea(promises, inset, angle || auto, spacing, poly.fill = []);
+            if (!outline && poly.fill.length) {
+                poly.fill = connect_lines(poly.fill, spacing * 2);
+            }
         }
         return true;
     });
diff --git a/src/kiri/init.js b/src/kiri/init.js
index 7cc22e3c..d6d8801e 100644
--- a/src/kiri/init.js
+++ b/src/kiri/init.js
@@ -1862,10 +1862,10 @@ gapp.register("kiri.init", [], (root, exports) => {
             sliceSupportArea:    uc.newInput(LANG.sp_area_s, {title:LANG.sp_area_l, bound:uc.bound(0.0,200.0), convert:uc.toFloat, modes:FDM}),
             sliceSupportExtra:   uc.newInput(LANG.sp_xpnd_s, {title:LANG.sp_xpnd_l, bound:uc.bound(0.0,200.0), convert:uc.toFloat, modes:FDM}),
             fdmSep:              uc.newBlank({class:"pop-sep", modes:FDM}),
-            sliceSupportAngle:   uc.newInput(LANG.sp_angl_s, {title:LANG.sp_angl_l, bound:uc.bound(0.0,90.0), convert:uc.toFloat, modes:FDM, show:() => !ui.sliceSupportEnable.checked}),
+            sliceSupportAngle:   uc.newInput(LANG.sp_angl_s, {title:LANG.sp_angl_l, bound:uc.bound(0.0,90.0), convert:uc.toFloat, modes:FDM}),
             sliceSupportSpan:    uc.newInput(LANG.sp_span_s, {title:LANG.sp_span_l, bound:uc.bound(0.0,200.0), convert:uc.toFloat, modes:FDM, show:() => ui.sliceSupportEnable.checked}),
             sliceSupportEnable:  uc.newBoolean(LANG.sp_auto_s, onBooleanClick, {title:LANG.sp_auto_l, modes:FDM, show:isNotBelt}),
-            sliceSupportOutline: uc.newBoolean(LANG.sp_outl_s, onBooleanClick, {title:LANG.sp_outl_l, modes:FDM, show:() => !ui.sliceSupportEnable.checked}),
+            sliceSupportOutline: uc.newBoolean(LANG.sp_outl_s, onBooleanClick, {title:LANG.sp_outl_l, modes:FDM}),
 
             sliceSupportGen:     uc.newRow([
                 ui.ssaGen = uc.newButton(LANG.sp_detect, onButtonClick, {class: "f-col grow a-center"})