diff --git a/idlib/geometry/Surface_SweptSpline.cpp b/idlib/geometry/Surface_SweptSpline.cpp
index 1132aa6..96552b8 100644
--- a/idlib/geometry/Surface_SweptSpline.cpp
+++ b/idlib/geometry/Surface_SweptSpline.cpp
@@ -159,7 +159,7 @@ void idSurface_SweptSpline::Tessellate( const int splineSubdivisions, const int
 
 	// calculate the points and first derivatives for the swept spline
 	totalTime = sweptSpline->GetTime( sweptSpline->GetNumValues() - 1 ) - sweptSpline->GetTime( 0 ) + sweptSpline->GetCloseTime();
-	sweptSplineDiv = sweptSpline->GetBoundaryType() == idCurve_Spline<idVec3>::BT_CLOSED ? sweptSplineSubdivisions : sweptSplineSubdivisions - 1;
+	sweptSplineDiv = sweptSpline->GetBoundaryType() == idCurve_Spline<idVec4>::BT_CLOSED ? sweptSplineSubdivisions : sweptSplineSubdivisions - 1;
 	baseOffset = (splineSubdivisions-1) * sweptSplineSubdivisions;
 	for ( i = 0; i < sweptSplineSubdivisions; i++ ) {
 		t = totalTime * i / sweptSplineDiv;
@@ -172,7 +172,7 @@ void idSurface_SweptSpline::Tessellate( const int splineSubdivisions, const int
 
 	// sweep the spline
 	totalTime = spline->GetTime( spline->GetNumValues() - 1 ) - spline->GetTime( 0 ) + spline->GetCloseTime();
-	splineDiv = spline->GetBoundaryType() == idCurve_Spline<idVec3>::BT_CLOSED ? splineSubdivisions : splineSubdivisions - 1;
+	splineDiv = spline->GetBoundaryType() == idCurve_Spline<idVec4>::BT_CLOSED ? splineSubdivisions : splineSubdivisions - 1;
 	splineMat.Identity();
 	for ( i = 0; i < splineSubdivisions; i++ ) {
 		t = totalTime * i / splineDiv;