diff --git a/modules/gfx/src/impl/fast_spheres.hh b/modules/gfx/src/impl/fast_spheres.hh
index 2cef93d6561407b768586537851e5a5b83f7011a..72402ef9b36f81fca897f0a2484b39def3a7a932 100644
--- a/modules/gfx/src/impl/fast_spheres.hh
+++ b/modules/gfx/src/impl/fast_spheres.hh
@@ -30,7 +30,7 @@
 
 namespace ost { namespace gfx { namespace impl {
 
-  class FastSphereRenderer {
+  class DLLEXPORT_OST_GFX FastSphereRenderer {
   public:
     struct VData
     {