diff --git a/src/viewr.f90 b/src/viewr.f90
index c89c95b3..e2337b75 100644
--- a/src/viewr.f90
+++ b/src/viewr.f90
@@ -1323,7 +1323,7 @@ subroutine set3d(iplot,xyz,nxyz)
          enddo
          i=i+2+2*nn
          j=j+1
-         if (j.lt.length) then
+         if (j.gt.length) then
             call error('set3d','array overflow, increase the length parameter',' ')
          endif
       endif