diff --git a/src/mol-model-props/computed/interactions/contacts.ts b/src/mol-model-props/computed/interactions/contacts.ts
index c7baeb299ee0961e394d18a8510432a5841aaeee..9c85398e1d6058d1d80a4361454d465462c5a1bf 100644
--- a/src/mol-model-props/computed/interactions/contacts.ts
+++ b/src/mol-model-props/computed/interactions/contacts.ts
@@ -65,9 +65,10 @@ function isMember(element: StructureElement.UnitIndex, info: Features.Info) {
     return false
 }
 
-function setPosition(v: Vec3, info: Features.Info) {
-    Vec3.set(v, info.x[info.feature], info.y[info.feature], info.z[info.feature])
-    Vec3.transformMat4(v, v, info.unit.conformation.operator.matrix)
+function setPosition(out: Vec3, info: Features.Info) {
+    Vec3.set(out, info.x[info.feature], info.y[info.feature], info.z[info.feature])
+    Vec3.transformMat4(out, out, info.unit.conformation.operator.matrix)
+    return out
 }
 
 const tmpVec = Vec3()
diff --git a/src/mol-model-props/computed/interactions/features.ts b/src/mol-model-props/computed/interactions/features.ts
index 9e40471421afe4f139c064bc194c18da0d6a0db1..9bf69761a79ab977636238509c77ba0a44e8cfa9 100644
--- a/src/mol-model-props/computed/interactions/features.ts
+++ b/src/mol-model-props/computed/interactions/features.ts
@@ -10,6 +10,7 @@ import { GridLookup3D } from '../../../mol-math/geometry';
 import { OrderedSet, SortedArray } from '../../../mol-data/int';
 import { FeatureGroup, FeatureType } from './common';
 import { ValenceModelProvider } from '../valence-model';
+import { Vec3 } from '../../../mol-math/linear-algebra';
 
 export { Features }
 
@@ -40,6 +41,12 @@ namespace Features {
     /** Index into Features data arrays */
     export type FeatureIndex = { readonly '@type': 'feature-index' } & number
 
+    export function setPosition(out: Vec3, unit: Unit, index: FeatureIndex, features: Features) {
+        Vec3.set(out, features.x[index], features.y[index], features.z[index])
+        Vec3.transformMat4(out, out, unit.conformation.operator.matrix)
+        return out
+    }
+
     /** maps unit elements to features, range for unit element i is offsets[i] to offsets[i + 1] */
     export type ElementsIndex = {
         /** feature indices */
diff --git a/src/mol-model/loci.ts b/src/mol-model/loci.ts
index c379ae8eef94ba3db53757e23657d41cd8ebe0e2..b3771c937c43dc87883f66196f5ddc23e4df2fbd 100644
--- a/src/mol-model/loci.ts
+++ b/src/mol-model/loci.ts
@@ -15,6 +15,7 @@ import { Structure } from './structure/structure';
 import { PrincipalAxes } from '../mol-math/linear-algebra/matrix/principal-axes';
 import { ParamDefinition } from '../mol-util/param-definition';
 import { Interactions } from '../mol-model-props/computed/interactions/interactions';
+import { Features } from '../mol-model-props/computed/interactions/features';
 
 /** A Loci that includes every loci */
 export const EveryLoci = { kind: 'every-loci' as 'every-loci' }
@@ -118,7 +119,7 @@ namespace Loci {
         return loci
     }
 
-    const sphereHelper = new CentroidHelper(), tempPos = Vec3.zero();
+    const sphereHelper = new CentroidHelper(), tmpPos = Vec3.zero();
 
     export function getBoundingSphere(loci: Loci, boundingSphere?: Sphere3D): Sphere3D | undefined {
         if (loci.kind === 'every-loci' || loci.kind === 'empty-loci') return void 0;
@@ -129,24 +130,36 @@ namespace Loci {
         if (loci.kind === 'structure-loci') {
             return Sphere3D.copy(boundingSphere, loci.structure.boundary.sphere)
         } else if (loci.kind === 'element-loci') {
-            return StructureElement.Loci.getBoundary(loci).sphere;
+            return Sphere3D.copy(boundingSphere, StructureElement.Loci.getBoundary(loci).sphere);
         } else if (loci.kind === 'bond-loci') {
             for (const e of loci.bonds) {
-                e.aUnit.conformation.position(e.aUnit.elements[e.aIndex], tempPos);
-                sphereHelper.includeStep(tempPos);
-                e.bUnit.conformation.position(e.bUnit.elements[e.bIndex], tempPos);
-                sphereHelper.includeStep(tempPos);
+                e.aUnit.conformation.position(e.aUnit.elements[e.aIndex], tmpPos);
+                sphereHelper.includeStep(tmpPos);
+                e.bUnit.conformation.position(e.bUnit.elements[e.bIndex], tmpPos);
+                sphereHelper.includeStep(tmpPos);
             }
             sphereHelper.finishedIncludeStep();
             for (const e of loci.bonds) {
-                e.aUnit.conformation.position(e.aUnit.elements[e.aIndex], tempPos);
-                sphereHelper.radiusStep(tempPos);
-                e.aUnit.conformation.position(e.bUnit.elements[e.bIndex], tempPos);
-                sphereHelper.radiusStep(tempPos);
+                e.aUnit.conformation.position(e.aUnit.elements[e.aIndex], tmpPos);
+                sphereHelper.radiusStep(tmpPos);
+                e.aUnit.conformation.position(e.bUnit.elements[e.bIndex], tmpPos);
+                sphereHelper.radiusStep(tmpPos);
             }
         } else if (loci.kind === 'interaction-loci') {
-            // TODO
-            // return Interactions.Loci.getBoundary(loci).sphere;
+            const { unitsFeatures } = loci.interactions
+            for (const e of loci.contacts) {
+                Features.setPosition(tmpPos, e.unitA, e.indexA, unitsFeatures.get(e.unitA.id))
+                sphereHelper.includeStep(tmpPos)
+                Features.setPosition(tmpPos, e.unitB, e.indexB, unitsFeatures.get(e.unitB.id))
+                sphereHelper.includeStep(tmpPos);
+            }
+            sphereHelper.finishedIncludeStep();
+            for (const e of loci.contacts) {
+                Features.setPosition(tmpPos, e.unitA, e.indexA, unitsFeatures.get(e.unitA.id))
+                sphereHelper.radiusStep(tmpPos)
+                Features.setPosition(tmpPos, e.unitB, e.indexB, unitsFeatures.get(e.unitB.id))
+                sphereHelper.radiusStep(tmpPos);
+            }
         } else if (loci.kind === 'shape-loci') {
             // TODO
             return void 0;