diff --git a/src/matlab/+D3d/+Polygon/Make.m b/src/matlab/+D3d/+Polygon/Make.m
index 80b35e2ac5fd9922b6c5890e866eedd269a5179d..31efcdfc7498d0ea353691a7cc6660ff415aaf69 100644
--- a/src/matlab/+D3d/+Polygon/Make.m
+++ b/src/matlab/+D3d/+Polygon/Make.m
@@ -66,7 +66,7 @@ end
 
 norms = D3d.Polygon.CalcNorms(verts_xy,faces);
 
-polygon.index = polyIdx;
+polygon(1).index = polyIdx;
 polygon.frame = frame;
 polygon.label = label;
 polygon.color = color;