diff --git a/src/geo/base.js b/src/geo/base.js
index 9085a2d0..8326834e 100644
--- a/src/geo/base.js
+++ b/src/geo/base.js
@@ -461,6 +461,60 @@
         return out;
     }
 
+    // wrapper for earcut that handles higher order dimensions and finds the
+    // two with the greatest delta to pass to the earcut algorith, then returns
+    // an unwrapped array in the original dimensions
+    function triangulate(array, holes, dims) {
+        let narray, d1, d2;
+        if (dims === 2) {
+            narray = array;
+        } else {
+            let min = new Array(dims).fill(Infinity);
+            let max = new Array(dims).fill(-Infinity);
+            for (let i=0, l=array.length; i<l; ) {
+                for (let j=0, av; j<dims; j++) {
+                    av = array[i++];
+                    min[j] = Math.min(min[j], av);
+                    max[j] = Math.max(max[j], av);
+                }
+            }
+            let delta = new Array(dims);
+            for (let i=0; i<dims; i++) {
+                delta[i] = max[i] - min[i];
+            }
+            console.log({delta: delta.slice()});
+            let dmax = 0; //d1, d2, dmax = 0;
+            for (let i=0; i<dims; i++) {
+                if (delta[i] > dmax) {
+                    dmax = delta[i];
+                    d1 = i;
+                }
+            }
+            delta[d1] = dmax = 0;
+            for (let i=0; i<dims; i++) {
+                if (delta[i] > dmax) {
+                    dmax = delta[i];
+                    d2 = i;
+                }
+            }
+            narray = new Array((array.length / dims) * 2);
+            for (let i=0, j=0; i<array.length; i += dims) {
+                narray[j++] = array[i + d1];
+                narray[j++] = array[i + d2];
+            }
+        }
+        let ec = earcut(narray, holes, 2);
+        let oa = new Array(ec.length * dims);
+        for (let i=0, e=0, l=ec.length, ai; i<l; i++) {
+            ai = ec[i] * dims;
+            for (let j=0; j<dims; j++) {
+                oa[e++] = array[ ai + j ];
+            }
+        }
+        console.log({d1, d2, array, narray, ec, oa});
+        return oa;
+    }
+
     /** ******************************************************************
      * Connect to base
      ******************************************************************* */
@@ -566,6 +620,7 @@
         numOrDefault,
         orderClosest,
         zInPlane,
+        triangulate,
         comma: (v) => {
             if (!v) return v;
             let [lt,rt] = v.toString().split('.');
diff --git a/src/geo/csg.js b/src/geo/csg.js
new file mode 100644
index 00000000..d3152d39
--- /dev/null
+++ b/src/geo/csg.js
@@ -0,0 +1,448 @@
+// ## License
+//
+// Copyright (c) 2011 Evan Wallace (http://madebyevan.com/), under the MIT license.
+// Modified for GridApps by Stewart Allen (sa@grid.space)
+
+(function() {
+
+// dep: geo.base
+let base = self.base;
+if (base.CSG) return;
+
+// # class CSG
+// Holds a binary space partition tree representing a 3D solid. Two solids can
+// be combined using the `union()`, `subtract()`, and `intersect()` methods.
+class CSG {
+    constructor(polygons) {
+        this.polygons = polygons || [];
+    }
+
+    clone() {
+        let csg = new CSG();
+        csg.polygons = this.polygons.map(p=>p.clone())
+        return csg;
+    }
+
+    toPolygons() {
+        return this.polygons;
+    }
+
+    union(csg) {
+        let a = new Node(this.clone().polygons);
+        let b = new Node(csg.clone().polygons);
+        a.clipTo(b);
+        b.clipTo(a);
+        b.invert();
+        b.clipTo(a);
+        b.invert();
+        a.build(b.allPolygons());
+        return CSG.fromPolygons(a.allPolygons());
+    }
+
+    subtract(csg) {
+        let a = new Node(this.clone().polygons);
+        let b = new Node(csg.clone().polygons);
+        a.invert();
+        a.clipTo(b);
+        b.clipTo(a);
+        b.invert();
+        b.clipTo(a);
+        b.invert();
+        a.build(b.allPolygons());
+        a.invert();
+        return CSG.fromPolygons(a.allPolygons());
+    }
+
+    intersect(csg) {
+        let a = new Node(this.clone().polygons);
+        let b = new Node(csg.clone().polygons);
+        a.invert();
+        b.clipTo(a);
+        b.invert();
+        a.clipTo(b);
+        b.clipTo(a);
+        a.build(b.allPolygons());
+        a.invert();
+        return CSG.fromPolygons(a.allPolygons());
+    }
+
+    // Return a new CSG solid with solid and empty space switched. This solid is
+    // not modified.
+    inverse() {
+        let csg = this.clone();
+        csg.polygons.forEach(p=>p.flip());
+        return csg;
+    }
+}
+
+// Construct a CSG solid from a list of `Polygon` instances.
+CSG.fromPolygons = function(polygons) {
+    return new CSG(polygons);
+};
+
+// Construct a CSG from a THREE Geometry BufferAttribute array (or similar)
+CSG.fromPositionArray = function(array) {
+    let polys = [];
+    for (let i=0, l=array.length; i<l; ) {
+        polys.push(new Polygon([
+            new Vertex(new Vector(
+                array[i++],
+                array[i++],
+                array[i++],
+            )),
+            new Vertex(new Vector(
+                array[i++],
+                array[i++],
+                array[i++],
+            )),
+            new Vertex(new Vector(
+                array[i++],
+                array[i++],
+                array[i++],
+            )),
+        ]));
+    }
+    return CSG.fromPolygons(polys);
+};
+
+CSG.computeFaceNormal = function(vA,vB,vC) {
+    let cb = vC.clone().sub(vB);
+    let ab = vA.clone().sub(vB);
+    cb.cross(ab);
+    return cb.normalize();
+};
+
+// # class Vector
+class Vector {
+    constructor(x=0, y=0, z=0) {
+        this.x=x;
+        this.y=y;
+        this.z=z;
+    }
+    copy(v){
+        this.x=v.x;
+        this.y=v.y;
+        this.z=v.z;
+        return this
+    }
+    clone() {
+        return new Vector(this.x,this.y,this.z)
+    }
+    negate() {
+        this.x*=-1;
+        this.y*=-1;
+        this.z*=-1;
+        return this
+    }
+    add(a) {
+        this.x+=a.x
+        this.y+=a.y
+        this.z+=a.z
+        return this;
+    }
+    sub(a) {
+        this.x-=a.x
+        this.y-=a.y
+        this.z-=a.z
+        return this
+    }
+    times(a) {
+        this.x*=a
+        this.y*=a
+        this.z*=a
+        return this
+    }
+    dividedBy(a) {
+        this.x/=a
+        this.y/=a
+        this.z/=a
+        return this
+    }
+    lerp(a, t) {
+        return this.add(tv0.copy(a).sub(this).times(t))
+    }
+    unit() {
+        return this.dividedBy(this.length())
+    }
+    length(){
+        return Math.sqrt((this.x**2)+(this.y**2)+(this.z**2))
+    }
+    normalize(){
+        return this.unit()
+    }
+    cross(b) {
+        let a = this;
+        const ax = a.x, ay = a.y, az = a.z;
+        const bx = b.x, by = b.y, bz = b.z;
+
+        this.x = ay * bz - az * by;
+        this.y = az * bx - ax * bz;
+        this.z = ax * by - ay * bx;
+
+        return this;
+    }
+    dot(b){
+        return (this.x*b.x)+(this.y*b.y)+(this.z*b.z)
+    }
+}
+
+//Temporaries used to avoid internal allocation..
+let tv0 = new Vector()
+let tv1 = new Vector()
+
+// zero normal for Vertices when none provided
+let nnn = new Vector();
+
+// # class Vertex
+// Represents a vertex of a polygon. Use your own vertex class instead of this
+// one to provide additional features like texture coordinates and vertex
+// colors. Custom vertex classes need to provide a `pos` property and `clone()`,
+// `flip()`, and `interpolate()` methods that behave analogous to the ones
+// defined by `CSG.Vertex`. This class provides `normal` so convenience
+// functions like `CSG.sphere()` can return a smooth vertex normal, but `normal`
+// is not used anywhere else.
+class Vertex {
+    constructor(pos, normal, uv, color) {
+        this.pos = new Vector().copy(pos);
+        this.normal = new Vector().copy(normal || nnn);
+        uv && (this.uv = new Vector().copy(uv)) && (this.uv.z=0);
+        color && (this.color = new Vector().copy(color));
+    }
+
+    clone() {
+        return new Vertex(this.pos,this.normal,this.uv,this.color);
+    }
+
+    // Invert all orientation-specific data (e.g. vertex normal). Called when the
+    // orientation of a polygon is flipped.
+    flip() {
+        this.normal.negate();
+    }
+
+    // Create a new vertex between this vertex and `other` by linearly
+    // interpolating all properties using a parameter of `t`. Subclasses should
+    // override this to interpolate additional properties.
+    interpolate(other, t) {
+        return new Vertex(this.pos.clone().lerp(other.pos, t),this.normal.clone().lerp(other.normal, t),this.uv&&other.uv&&this.uv.clone().lerp(other.uv, t), this.color&&other.color&&this.color.clone().lerp(other.color,t))
+    }
+}
+
+// # class Plane
+// Represents a plane in 3D space.
+class Plane {
+    constructor(normal, w) {
+        this.normal = normal;
+        this.w = w;
+    }
+
+    clone() {
+        return new Plane(this.normal.clone(),this.w);
+    }
+
+    flip() {
+        this.normal.negate();
+        this.w = -this.w;
+    }
+
+    // Split `polygon` by this plane if needed, then put the polygon or polygon
+    // fragments in the appropriate lists. Coplanar polygons go into either
+    // `coplanarFront` or `coplanarBack` depending on their orientation with
+    // respect to this plane. Polygons in front or in back of this plane go into
+    // either `front` or `back`.
+    splitPolygon(polygon, coplanarFront, coplanarBack, front, back) {
+        const COPLANAR = 0;
+        const FRONT = 1;
+        const BACK = 2;
+        const SPANNING = 3;
+
+        // Classify each point as well as the entire polygon into one of the above
+        // four classes.
+        let polygonType = 0;
+        let types = [];
+        for (let i = 0; i < polygon.vertices.length; i++) {
+            let t = this.normal.dot(polygon.vertices[i].pos) - this.w;
+            let type = (t < -Plane.EPSILON) ? BACK : (t > Plane.EPSILON) ? FRONT : COPLANAR;
+            polygonType |= type;
+            types.push(type);
+        }
+
+        // Put the polygon in the correct list, splitting it when necessary.
+        switch (polygonType) {
+        case COPLANAR:
+            (this.normal.dot(polygon.plane.normal) > 0 ? coplanarFront : coplanarBack).push(polygon);
+            break;
+        case FRONT:
+            front.push(polygon);
+            break;
+        case BACK:
+            back.push(polygon);
+            break;
+        case SPANNING:
+            let f = []
+              , b = [];
+            for (let i = 0; i < polygon.vertices.length; i++) {
+                let j = (i + 1) % polygon.vertices.length;
+                let ti = types[i]
+                  , tj = types[j];
+                let vi = polygon.vertices[i]
+                  , vj = polygon.vertices[j];
+                if (ti != BACK)
+                    f.push(vi);
+                if (ti != FRONT)
+                    b.push(ti != BACK ? vi.clone() : vi);
+                if ((ti | tj) == SPANNING) {
+                    let t = (this.w - this.normal.dot(vi.pos)) / this.normal.dot(tv0.copy(vj.pos).sub(vi.pos));
+                    let v = vi.interpolate(vj, t);
+                    f.push(v);
+                    b.push(v.clone());
+                }
+            }
+            if (f.length >= 3)
+                front.push(new Polygon(f,polygon.shared));
+            if (b.length >= 3)
+                back.push(new Polygon(b,polygon.shared));
+            break;
+        }
+    }
+
+}
+
+// `Plane.EPSILON` is the tolerance used by `splitPolygon()` to decide if a
+// point is on the plane.
+Plane.EPSILON = 1e-5;
+
+Plane.fromPoints = function(a, b, c) {
+    let n = tv0.copy(b).sub(a).cross(tv1.copy(c).sub(a)).normalize()
+    return new Plane(n.clone(),n.dot(a));
+};
+
+// # class Polygon
+// Represents a convex polygon. The vertices used to initialize a polygon must
+// be coplanar and form a convex loop. They do not have to be `Vertex`
+// instances but they must behave similarly (duck typing can be used for
+// customization).
+//
+// Each convex polygon has a `shared` property, which is shared between all
+// polygons that are clones of each other or were split from the same polygon.
+// This can be used to define per-polygon properties (such as surface color).
+class Polygon {
+    constructor(vertices, shared) {
+        this.vertices = vertices;
+        this.shared = shared;
+        this.plane = Plane.fromPoints(vertices[0].pos, vertices[1].pos, vertices[2].pos);
+    }
+    clone() {
+        return new Polygon(this.vertices.map(v=>v.clone()),this.shared);
+    }
+    flip() {
+        this.vertices.reverse().forEach(v=>v.flip())
+        this.plane.flip();
+    }
+}
+
+// # class Node
+// Holds a node in a BSP tree. A BSP tree is built from a collection of polygons
+// by picking a polygon to split along. That polygon (and all other coplanar
+// polygons) are added directly to that node and the other polygons are added to
+// the front and/or back subtrees. This is not a leafy BSP tree since there is
+// no distinction between internal and leaf nodes.
+class Node {
+    constructor(polygons) {
+        this.plane = null;
+        this.front = null;
+        this.back = null;
+        this.polygons = [];
+        if (polygons)
+            this.build(polygons);
+    }
+    clone() {
+        let node = new Node();
+        node.plane = this.plane && this.plane.clone();
+        node.front = this.front && this.front.clone();
+        node.back = this.back && this.back.clone();
+        node.polygons = this.polygons.map(p=>p.clone());
+        return node;
+    }
+
+    // Convert solid space to empty space and empty space to solid space.
+    invert() {
+        for (let i = 0; i < this.polygons.length; i++)
+            this.polygons[i].flip();
+
+        this.plane && this.plane.flip();
+        this.front && this.front.invert();
+        this.back && this.back.invert();
+        let temp = this.front;
+        this.front = this.back;
+        this.back = temp;
+    }
+
+    // Recursively remove all polygons in `polygons` that are inside this BSP tree.
+    clipPolygons(polygons) {
+        if (!this.plane)
+            return polygons.slice();
+        let front = []
+          , back = [];
+        for (let i = 0; i < polygons.length; i++) {
+            this.plane.splitPolygon(polygons[i], front, back, front, back);
+        }
+        if (this.front)
+            front = this.front.clipPolygons(front);
+        if (this.back)
+            back = this.back.clipPolygons(back);
+        else
+            back = [];
+            //return front;
+        return front.concat(back);
+    }
+
+    // Remove all polygons in this BSP tree that are inside the other BSP tree `bsp`.
+    clipTo(bsp) {
+        this.polygons = bsp.clipPolygons(this.polygons);
+        if (this.front)
+            this.front.clipTo(bsp);
+        if (this.back)
+            this.back.clipTo(bsp);
+    }
+
+    // Return a list of all polygons in this BSP tree.
+    allPolygons() {
+        let polygons = this.polygons.slice();
+        if (this.front)
+            polygons = polygons.concat(this.front.allPolygons());
+        if (this.back)
+            polygons = polygons.concat(this.back.allPolygons());
+        return polygons;
+    }
+
+    // Build a BSP tree out of `polygons`. When called on an existing tree, the
+    // new polygons are filtered down to the bottom of the tree and become new
+    // nodes there. Each set of polygons is partitioned using the first polygon
+    // (no heuristic is used to pick a good split).
+    build(polygons) {
+        if (!polygons.length)
+            return;
+        if (!this.plane)
+            this.plane = polygons[0].plane.clone();
+        let front = []
+          , back = [];
+        for (let i = 0; i < polygons.length; i++) {
+            this.plane.splitPolygon(polygons[i], this.polygons, this.polygons, front, back);
+        }
+        if (front.length) {
+            if (!this.front)
+                this.front = new Node();
+            this.front.build(front);
+        }
+        if (back.length) {
+            if (!this.back)
+                this.back = new Node();
+            this.back.build(back);
+        }
+    }
+}
+
+// add to base objects
+base.CSG = { Solid: CSG, Vector, Vertex, Plane, Node };
+
+})();
diff --git a/src/mesh/api.js b/src/mesh/api.js
index 0b896c8d..df369b68 100644
--- a/src/mesh/api.js
+++ b/src/mesh/api.js
@@ -367,7 +367,7 @@ let tool = {
             mesh.api.group.new(models)
                 .centerModels()
                 .position(mid.x, mid.y, mid.z)
-                .select();
+                .setSelected();
         });
     },
 
@@ -391,7 +391,7 @@ let tool = {
         }
         Promise.all(promises).then(() => {
             if (newmdl.length) {
-                mesh.api.group.new(newmdl, undefined, "patch").select();
+                mesh.api.group.new(newmdl, undefined, "patch").setSelected();
             }
             api.log.emit('analysis complete').unpin();
         });
@@ -405,6 +405,10 @@ let tool = {
                 id: m.id, opt
             }).then(data => {
                 if (data) {
+                    // mesh.api.group.new([new mesh.model({
+                    //     file: `healed`,
+                    //     mesh: data.vertices
+                    // })]).floor().centerXY().setSelected();
                     m.reload(
                         data.vertices,
                         data.indices,
diff --git a/src/mesh/work.js b/src/mesh/work.js
index 888d5dd0..3fd5103f 100644
--- a/src/mesh/work.js
+++ b/src/mesh/work.js
@@ -16,6 +16,7 @@ moto.client.start(`/code/mesh_pool?${gapp.version}`, moto.client.max() * 0);
 // dep: geo.polygons
 // dep: geo.bounds
 // dep: geo.slicer
+// dep: geo.csg
 // dep: ext.clip2
 gapp.finalize("mesh.work", [
     "moto.license", // dep: moto.license
@@ -243,8 +244,29 @@ let model = {
         let { id, opt } = data;
         let tool = analyze(id, opt);
         log(`${id} | unrolling...`);
+        let unrolled = tool.unrolled();
+
+        // log(`${id} | intersecting...`);
+        // let box = new THREE.BoxGeometry(10000, 10000, 10000).attributes.position.array;
+        // box = base.CSG.Solid.fromPositionArray(box);
+        //
+        // let solid = base.CSG.Solid.fromPositionArray(unrolled);
+        // // let inter = box.intersect(solid);
+        // let inter = solid.union(solid.clone());
+        // let ears = inter.polygons
+        //     .map(p => p.vertices.map(v => v.pos))
+        //     .map(a => {
+        //         let pa = a.map( v => [ v.x, v.y, v.z ]).flat().map(v => v.round(2));
+        //         let ec = base.util.triangulate(pa, undefined, 3);
+        //         console.log({pa, ec});
+        //         return ec;
+        //     });//.flat();
+        //
+        // console.log({solid, inter, ears, ef: ears.flat()});
+        // unrolled = ears.flat();
+
         return {
-            vertices: tool.unrolled().toFloat32(),
+            vertices: unrolled.toFloat32(),
         };
     },
 
@@ -295,7 +317,7 @@ let model = {
 
     rebuild(data, send) {
         send.async();
-        let { id, matrix } = data;
+        let { id, matrix, mode } = data;
         log(`${id} | rebuilding...`);
         let points = translate_encode(id, matrix);
         log(`${id} | ${points.length} points`);