diff --git a/code/AssetLib/FBX/FBXExporter.cpp b/code/AssetLib/FBX/FBXExporter.cpp
index 322161411..e519f7e77 100644
--- a/code/AssetLib/FBX/FBXExporter.cpp
+++ b/code/AssetLib/FBX/FBXExporter.cpp
@@ -1789,13 +1789,13 @@ void FBXExporter::WriteObjects ()
             blendchannel_uid, blendshape_name + FBX::SEPARATOR + "SubDeformer", "BlendShapeChannel"
         );
         sdnode.AddChild("Version", int32_t(100));
-        sdnode.AddChild("DeformPercent", int32_t(100));
+        sdnode.AddChild("DeformPercent", float_t(0.0));
         FBX::Node p("Properties70");
-        p.AddP70numberA("DeformPercent", 100.);
+        p.AddP70numberA("DeformPercent", 0.0);
         sdnode.AddChild(p);
         // TODO: Normally just one weight per channel, adding stub for later development
         std::vector<float>fFullWeights;
-        fFullWeights.push_back(0.);
+        fFullWeights.push_back(100.);
         sdnode.AddChild("FullWeights", fFullWeights);
         sdnode.Dump(outstream, binary, indent);
 
diff --git a/code/Common/ImporterRegistry.cpp b/code/Common/ImporterRegistry.cpp
index a902fc89d..ddfcf6798 100644
--- a/code/Common/ImporterRegistry.cpp
+++ b/code/Common/ImporterRegistry.cpp
@@ -48,6 +48,7 @@ corresponding preprocessor flag to selectively disable formats.
 
 #include <assimp/BaseImporter.h>
 #include <vector>
+#include <cstdlib>
 
 // ------------------------------------------------------------------------------------------------
 // Importers
@@ -204,7 +205,17 @@ corresponding preprocessor flag to selectively disable formats.
 namespace Assimp {
 
 // ------------------------------------------------------------------------------------------------
-void GetImporterInstanceList(std::vector<BaseImporter *> &out) {
+void GetImporterInstanceList(std::vector<BaseImporter *> &out) {    
+    
+    // Some importers may be unimplemented or otherwise unsuitable for general use
+    // in their current state. Devs can set ASSIMP_ENABLE_DEV_IMPORTERS in their
+    // local environment to enable them, otherwise they're left out of the registry.
+    const char *envStr = std::getenv("ASSIMP_ENABLE_DEV_IMPORTERS");
+    bool devImportersEnabled = envStr && strcmp(envStr, "0");
+
+    // Ensure no unused var warnings if all uses are #ifndef'd away below:
+    (void)devImportersEnabled;
+
     // ----------------------------------------------------------------------------
     // Add an instance of each worker class here
     // (register_new_importers_here)
@@ -354,7 +365,9 @@ void GetImporterInstanceList(std::vector<BaseImporter *> &out) {
     out.push_back(new D3MFImporter());
 #endif
 #ifndef ASSIMP_BUILD_NO_X3D_IMPORTER
-    out.push_back(new X3DImporter());
+    if (devImportersEnabled) { // https://github.com/assimp/assimp/issues/3647
+        out.push_back(new X3DImporter());
+    }
 #endif
 #ifndef ASSIMP_BUILD_NO_MMD_IMPORTER
     out.push_back(new MMDImporter());
diff --git a/port/PyAssimp/pyassimp/structs.py b/port/PyAssimp/pyassimp/structs.py
index 809afae54..e1fba1950 100644
--- a/port/PyAssimp/pyassimp/structs.py
+++ b/port/PyAssimp/pyassimp/structs.py
@@ -1,6 +1,6 @@
 #-*- coding: utf-8 -*-
 
-from ctypes import POINTER, c_void_p, c_uint, c_char, c_float, Structure, c_char_p, c_double, c_ubyte, c_size_t, c_uint32
+from ctypes import POINTER, c_void_p, c_uint, c_char, c_float, Structure, c_double, c_ubyte, c_size_t, c_uint32
 
 
 class Vector2D(Structure):
@@ -1121,7 +1121,7 @@ class Scene(Structure):
             ("mMetadata", POINTER(Metadata)),
 
             # Internal data, do not touch
-            ("mPrivate", c_char_p),
+            ("mPrivate", POINTER(c_char)),
         ]
 
 assimp_structs_as_tuple = (Matrix4x4,