Fixed Duplicate and Input nodes creating objects only once in a for-loop

helper.py

@@ -1,3 +1,4 @@
+import re
 import bpy
 from mathutils import Vector
 
@@ -188,4 +189,20 @@ def selection_type_to_string(sel_type):
     if "FACE" in sel_type:
         out.append("Face")
 
-    return " + ".join(out)
+    return " + ".join(out)
+
+re_trailing_number = re.compile(r'\.(\d{3})$')
+def strip_trailing_number(s):
+    """ Strip trailing number such as ".001". """
+    m = re_trailing_number.match(s)
+    return s[0:-4] if m else s
+
+def unique_name(base_name):
+    """ Generate unique object name in `bpy.data.objects`. """
+    base_name = strip_trailing_number(base_name)
+    count = 1
+    name = base_name
+    while bpy.data.objects.get(name):
+        name = "%s.%03d" % (base_name, count)
+        count += 1
+    return name

nodes/_base/node_input.py

@@ -2,12 +2,12 @@
 
 from bpy.props import PointerProperty, StringProperty, BoolProperty
 from .._base.node_base import ScNode
-from ...helper import focus_on_object, remove_object
+from ...helper import focus_on_object, remove_object, print_log, unique_name
 
 class ScInputNode(ScNode):
     in_name: StringProperty(default="Object", update=ScNode.update_value)
     # in_uv: BoolProperty(default=True, update=ScNode.update_value)
-    out_mesh: PointerProperty(type=bpy.types.Object)
+    generated_objects: StringProperty(default="[]")
 
     def init(self, context):
         self.node_executable = True
@@ -16,20 +16,44 @@ def init(self, context):
         # self.inputs.new("ScNodeSocketBool", "Generate UVs").init("in_uv")
         self.outputs.new("ScNodeSocketObject", "Object")
 
+    def copy(self, node):
+        super().copy(node)
+        self.generated_objects = "[]"
+
     def error_condition(self):
         return (
             self.inputs["Name"].default_value == ""
         )
 
     def pre_execute(self):
-        focus_on_object(self.out_mesh)
-        remove_object(self.out_mesh)
+        # Clear generated objects
+        # Check "first_time" to prevent unexpected deletion inside for-loop
+        if (self.first_time):
+            for obj in eval(self.generated_objects):
+                # When obj is already deleted, remove_object() raises some exception.
+                try:
+                    remove_object(eval(obj))
+                except:
+                    print_log(self.name, None, "pre_execute",
+                              "Invalid object: " + repr(obj))
+            self.generated_objects = "[]"
 
     def post_execute(self):
+        # WORKAROUND
+        # Normally, Blender automatically makes the name of the object unique.
+        # But we lose the old object because the name is overwritten by the
+        # new object. We need to keep the old object's name and manually give
+        # the new object a new unique name.
+        name = unique_name(self.inputs["Name"].default_value)
+        out_mesh = bpy.context.active_object
+        out_mesh.name = name
+        if (out_mesh.data):
+            out_mesh.data.name = out_mesh.name
+
+        tmp = eval(self.generated_objects)
+        tmp.append(repr(out_mesh))
+        self.generated_objects = repr(tmp)
+
         out = {}
-        self.out_mesh = bpy.context.active_object
-        self.out_mesh.name = self.inputs["Name"].default_value
-        if (self.out_mesh.data):
-            self.out_mesh.data.name = self.out_mesh.name
-        out["Object"] = self.out_mesh
-        return out
+        out["Object"] = out_mesh
+        return out

nodes/object_operators/ScDuplicateObject.py

@@ -1,27 +1,47 @@
 import bpy
 
-from bpy.props import FloatProperty
+from bpy.props import FloatProperty, StringProperty
 from bpy.types import Node
 from .._base.node_base import ScNode
 from .._base.node_operator import ScObjectOperatorNode
-from ...helper import remove_object
+from ...helper import remove_object, print_log
 
 class ScDuplicateObject(Node, ScObjectOperatorNode):
     bl_idname = "ScDuplicateObject"
     bl_label = "Duplicate Object"
+
+    generated_objects: StringProperty(default="[]")
 
     def init(self, context):
         super().init(context)
         self.outputs.new("ScNodeSocketObject", "Duplicate Object")
 
+    def copy(self, node):
+        super().copy(node)
+        self.generated_objects = "[]"
+
     def pre_execute(self):
-        remove_object(self.outputs["Duplicate Object"].default_value)
+        # Check first_time to prevent unexpected deletion inside for-loop
+        if (self.first_time):
+            for obj in eval(self.generated_objects):
+                # When obj is already deleted, remove_object() raises some exception.
+                try:
+                    remove_object(eval(obj))
+                except:
+                    print_log(self.name, None, "pre_execute",
+                              "Invalid object: " + repr(obj))
+            self.generated_objects = "[]"
         super().pre_execute()
 
     def functionality(self):
         bpy.ops.object.duplicate()
 
     def post_execute(self):
+        # Store duplicated object to delete it before re-execute this node.
+        tmp = eval(self.generated_objects)
+        tmp.append(repr(bpy.context.active_object))
+        self.generated_objects = repr(tmp)
+
         out = super().post_execute()
         out["Duplicate Object"] = bpy.context.active_object
-        return out
+        return out