fix(modeling): corrected hull of single unconvex solid

packages/modeling/src/operations/hulls/hull.test.js

@@ -2,7 +2,9 @@ const test = require('ava')
 
 const { geom2, geom3, path2 } = require('../../geometries')
 
-const { sphere, cuboid, ellipsoid } = require('../../primitives')
+const { measureVolume } = require('../../measurements')
+
+const { sphere, cuboid, ellipsoid, torus } = require('../../primitives')
 
 const { center } = require('../transforms/center')
 
@@ -274,3 +276,9 @@ test('hull (multiple, overlapping, geom3)', (t) => {
   t.notThrows(() => geom3.validate(obs))
   t.is(pts.length, 92)
 })
+
+test('hull (single, unconvex, geom3)', (t) => {
+  const geometry = torus()
+  const obs = hull(geometry)
+  t.assert(measureVolume(obs) > measureVolume(geometry))
+})

packages/modeling/src/operations/hulls/hullGeom3.js

@@ -16,11 +16,11 @@ const hullPoints3 = require('./hullPoints3')
 const hullGeom3 = (...geometries) => {
   geometries = flatten(geometries)
 
-  if (geometries.length === 1) return geometries[0]
-
   // extract the unique vertices from the geometries
   const unique = toUniquePoints(geometries)
 
+  if (unique.length === 0) return geom3.create()
+
   return geom3.create(hullPoints3(unique))
 }