diff --git a/jme3-blender/src/main/java/com/jme3/scene/plugins/blender/constraints/definitions/ConstraintDefinitionDistLimit.java b/jme3-blender/src/main/java/com/jme3/scene/plugins/blender/constraints/definitions/ConstraintDefinitionDistLimit.java
index 5185d1646..cc4852cca 100644
--- a/jme3-blender/src/main/java/com/jme3/scene/plugins/blender/constraints/definitions/ConstraintDefinitionDistLimit.java
+++ b/jme3-blender/src/main/java/com/jme3/scene/plugins/blender/constraints/definitions/ConstraintDefinitionDistLimit.java
@@ -34,6 +34,9 @@ import com.jme3.scene.plugins.blender.file.Structure;
             // distance limit does not work on bones who are connected to their parent
             return;
         }
+        if(influence == 0 || targetTransform == null) {
+            return ;// no need to do anything
+        }
         
         Transform ownerTransform = this.getOwnerTransform(ownerSpace);
 
diff --git a/jme3-blender/src/main/java/com/jme3/scene/plugins/blender/constraints/definitions/ConstraintDefinitionIK.java b/jme3-blender/src/main/java/com/jme3/scene/plugins/blender/constraints/definitions/ConstraintDefinitionIK.java
index d25e61b3b..615291999 100644
--- a/jme3-blender/src/main/java/com/jme3/scene/plugins/blender/constraints/definitions/ConstraintDefinitionIK.java
+++ b/jme3-blender/src/main/java/com/jme3/scene/plugins/blender/constraints/definitions/ConstraintDefinitionIK.java
@@ -53,12 +53,15 @@ public class ConstraintDefinitionIK extends ConstraintDefinition {
 
     @Override
     public void bake(Space ownerSpace, Space targetSpace, Transform targetTransform, float influence) {
-        if (influence == 0 || !needToCompute) {
+        if (influence == 0 || !needToCompute || targetTransform == null) {
             return;// no need to do anything
         }
         Quaternion q = new Quaternion();
         Vector3f t = targetTransform.getTranslation();
         List<BoneContext> bones = this.loadBones();
+        if(bones.size() == 0) {
+            return;// no need to do anything
+        }
         float distanceFromTarget = Float.MAX_VALUE;
 
         int iterations = this.iterations;
diff --git a/jme3-blender/src/main/java/com/jme3/scene/plugins/blender/constraints/definitions/ConstraintDefinitionLocLike.java b/jme3-blender/src/main/java/com/jme3/scene/plugins/blender/constraints/definitions/ConstraintDefinitionLocLike.java
index e2516e658..0e2c4d63d 100644
--- a/jme3-blender/src/main/java/com/jme3/scene/plugins/blender/constraints/definitions/ConstraintDefinitionLocLike.java
+++ b/jme3-blender/src/main/java/com/jme3/scene/plugins/blender/constraints/definitions/ConstraintDefinitionLocLike.java
@@ -49,6 +49,9 @@ import com.jme3.scene.plugins.blender.file.Structure;
             // location copy does not work on bones who are connected to their parent
             return;
         }
+        if(influence == 0 || targetTransform == null) {
+            return ;// no need to do anything
+        }
         
         Transform ownerTransform = this.getOwnerTransform(ownerSpace);
         
diff --git a/jme3-blender/src/main/java/com/jme3/scene/plugins/blender/constraints/definitions/ConstraintDefinitionRotLike.java b/jme3-blender/src/main/java/com/jme3/scene/plugins/blender/constraints/definitions/ConstraintDefinitionRotLike.java
index 24a91bfb9..3a363cb4d 100644
--- a/jme3-blender/src/main/java/com/jme3/scene/plugins/blender/constraints/definitions/ConstraintDefinitionRotLike.java
+++ b/jme3-blender/src/main/java/com/jme3/scene/plugins/blender/constraints/definitions/ConstraintDefinitionRotLike.java
@@ -29,6 +29,9 @@ import com.jme3.scene.plugins.blender.file.Structure;
 
     @Override
     public void bake(Space ownerSpace, Space targetSpace, Transform targetTransform, float influence) {
+        if(influence == 0 || targetTransform == null) {
+            return ;// no need to do anything
+        }
         Transform ownerTransform = this.getOwnerTransform(ownerSpace);
         
         Quaternion ownerRotation = ownerTransform.getRotation();
diff --git a/jme3-blender/src/main/java/com/jme3/scene/plugins/blender/constraints/definitions/ConstraintDefinitionSizeLike.java b/jme3-blender/src/main/java/com/jme3/scene/plugins/blender/constraints/definitions/ConstraintDefinitionSizeLike.java
index 2b86a5c86..046801526 100644
--- a/jme3-blender/src/main/java/com/jme3/scene/plugins/blender/constraints/definitions/ConstraintDefinitionSizeLike.java
+++ b/jme3-blender/src/main/java/com/jme3/scene/plugins/blender/constraints/definitions/ConstraintDefinitionSizeLike.java
@@ -32,6 +32,9 @@ import com.jme3.scene.plugins.blender.file.Structure;
     
     @Override
     public void bake(Space ownerSpace, Space targetSpace, Transform targetTransform, float influence) {
+        if(influence == 0 || targetTransform == null) {
+            return;// no need to do anything
+        }
         Transform ownerTransform = this.getOwnerTransform(ownerSpace);
         
         Vector3f ownerScale = ownerTransform.getScale();
diff --git a/jme3-blender/src/main/java/com/jme3/scene/plugins/blender/constraints/definitions/ConstraintDefinitionTransLike.java b/jme3-blender/src/main/java/com/jme3/scene/plugins/blender/constraints/definitions/ConstraintDefinitionTransLike.java
index d58907ea9..5b171b97f 100644
--- a/jme3-blender/src/main/java/com/jme3/scene/plugins/blender/constraints/definitions/ConstraintDefinitionTransLike.java
+++ b/jme3-blender/src/main/java/com/jme3/scene/plugins/blender/constraints/definitions/ConstraintDefinitionTransLike.java
@@ -35,6 +35,9 @@ public class ConstraintDefinitionTransLike extends ConstraintDefinition {
 
     @Override
     public void bake(Space ownerSpace, Space targetSpace, Transform targetTransform, float influence) {
+        if(influence == 0 || targetTransform == null) {
+            return ;// no need to do anything
+        }
         Object target = this.getTarget();// Bone or Node
         Object owner = this.getOwner();// Bone or Node
         if (!target.getClass().equals(owner.getClass())) {