Tree supports: Switched to new Organic smoothing & collision avoidance.

Follow-up to 3d9f39e258
which had the new smoothing & collision avoidance disabled by mistake.

src/libslic3r/TreeSupport.cpp

@@ -21,8 +21,6 @@
 #include "MutablePolygon.hpp"
 #include "SupportMaterial.hpp"
 #include "TriangleMeshSlicer.hpp"
-#include "OpenVDBUtilsLegacy.hpp"
-#include <openvdb/tools/VolumeToSpheres.h>
 
 #include <cassert>
 #include <chrono>
@@ -45,6 +43,14 @@
     #define TREE_SUPPORT_SHOW_ERRORS_WIN32
 #endif
 
+// #define TREE_SUPPORT_ORGANIC_NUDGE_NEW 1
+
+#ifndef TREE_SUPPORT_ORGANIC_NUDGE_NEW
+    // Old version using OpenVDB, works but it is extremely slow for complex meshes.
+    #include "OpenVDBUtilsLegacy.hpp"
+    #include <openvdb/tools/VolumeToSpheres.h>
+#endif // TREE_SUPPORT_ORGANIC_NUDGE_NEW
+
 namespace Slic3r
 {
 
@@ -3389,8 +3395,6 @@ static void extrude_branch(
 }
 #endif
 
-// #define TREE_SUPPORT_ORGANIC_NUDGE_NEW 1
-
 #ifdef TREE_SUPPORT_ORGANIC_NUDGE_NEW
 // New version using per layer AABB trees of lines for nudging spheres away from an object.
 static void organic_smooth_branches_avoid_collisions(