diff --git a/src/mol-repr/structure/visual/util/polymer/trace-iterator.ts b/src/mol-repr/structure/visual/util/polymer/trace-iterator.ts
index 4b3e38c4558eb15a02e4a5adea2d173619e913db..d29292d89377fb4553e52a85c30617fa700414ee 100644
--- a/src/mol-repr/structure/visual/util/polymer/trace-iterator.ts
+++ b/src/mol-repr/structure/visual/util/polymer/trace-iterator.ts
@@ -119,7 +119,8 @@ export class AtomicPolymerTraceIterator implements Iterator<PolymerTraceElement>
     }
 
     private setControlPoint(out: Vec3, p1: Vec3, p2: Vec3, p3: Vec3, residueIndex: ResidueIndex) {
-        if (SecondaryStructureType.is(this.currSecStrucType, SecondaryStructureType.Flag.Beta)) {
+        const ss =  this.secondaryStructureType[residueIndex]
+        if (SecondaryStructureType.is(ss, SecondaryStructureType.Flag.Beta)) {
             Vec3.scale(out, Vec3.add(out, p1, Vec3.add(out, p3, Vec3.add(out, p2, p2))), 1/4)
         } else {
             Vec3.copy(out, p2)