Call Operator With Tweak Popup Window In Blender Python

by JurnalWarga.com 56 views
Iklan Headers

Hey guys! Today, we're diving into creating custom operators in Blender using Python, specifically focusing on how to tweak popup windows and handle different actions based on key presses like CTRL. This is super useful when you want to add extra functionality to your modeling tools, making your workflow smoother and more efficient. Let’s get started!

Introduction to Custom Operators in Blender

Custom operators are the backbone of extending Blender's functionality. These operators allow you to create buttons, menu items, and tools that perform specific actions tailored to your needs. Think of operators as mini-programs that execute when triggered, and they can do almost anything – from simple tasks like merging vertices to complex operations like generating intricate models. Understanding how to create and manipulate these operators is crucial for any serious Blender scripter.

Why Custom Operators?

So, why bother with custom operators? Well, the main reason is flexibility. Blender is powerful out of the box, but sometimes you need a tool that does something very specific. Custom operators let you bridge that gap. They also help in:

  • Efficiency: Automate repetitive tasks.
  • Customization: Tailor Blender to your workflow.
  • Consistency: Ensure actions are performed the same way every time.
  • Sharing: Distribute your tools to other users.

Basic Structure of a Blender Operator

Before we jump into the code, let's look at the basic structure of a Blender operator:

import bpy

class MyCustomOperator(bpy.types.Operator):
    bl_idname = "object.my_custom_operator" # Unique identifier
    bl_label = "My Custom Operator" # Display name
    bl_options = {'REGISTER', 'UNDO'} # Operator behavior

    def execute(self, context):
        # Main code that performs the action
        return {'FINISHED'}

def register():
    bpy.utils.register_class(MyCustomOperator)

def unregister():
    bpy.utils.unregister_class(MyCustomOperator)

if __name__ == "__main__":
    register()
  • bl_idname: This is the unique identifier for your operator. Blender uses this to find and call your operator, so it needs to be unique across all operators.
  • bl_label: This is the name that appears in menus and buttons.
  • bl_options: This setting controls how the operator behaves. {'REGISTER', 'UNDO'} means the operator can be undone and will be registered with Blender.
  • execute(self, context): This is the main function where your code goes. It’s called when the operator is executed. The context object gives you access to the current Blender scene, selected objects, and much more.

Implementing Merge Vertices with Tweak Popup

Now, let’s tackle the specific problem: merging vertices by distance with a tweak popup and a CTRL-click alternative. The goal is to have a button that, when clicked, merges vertices by distance using default settings. But if the user holds CTRL while clicking, a popup window should appear, allowing them to adjust the merge distance.

Setting Up the Operator

First, we need to create the operator class. We'll set up the bl_idname and bl_label, and include the execute function where the main logic will reside.

import bpy

class MergeVerticesOperator(bpy.types.Operator):
    bl_idname = "mesh.merge_vertices_by_distance_tweak"
    bl_label = "Merge Vertices"
    bl_options = {'REGISTER', 'UNDO'}

    def execute(self, context):
        # Main logic goes here
        return {'FINISHED'}

    def invoke(self, context, event):
        # Invoke logic goes here
        return context.window_manager.invoke_props_dialog(self)


def register():
    bpy.utils.register_class(MergeVerticesOperator)

def unregister():
    bpy.utils.unregister_class(MergeVerticesOperator)

if __name__ == "__main__":
    register()

Handling CTRL-Click with invoke

The key to handling the CTRL-click is the invoke function. This function is called before execute and allows us to check for modifier keys (like CTRL) and decide what to do. If CTRL is pressed, we’ll show the properties dialog; otherwise, we’ll execute the merge operation directly.

    def invoke(self, context, event):
        if event.ctrl:
            return context.window_manager.invoke_props_dialog(self)
        else:
            return self.execute(context)

Here, event.ctrl checks if the CTRL key is pressed. If it is, we call context.window_manager.invoke_props_dialog(self), which opens the tweak popup window. If not, we call self.execute(context) to run the merge operation directly.

Implementing the execute Function

Now, let’s implement the execute function. This function will perform the merge operation, either with default settings or with the settings from the tweak popup.

    def execute(self, context):
        bpy.ops.mesh.remove_doubles()
        return {'FINISHED'}

For the default action (no CTRL key), we simply call bpy.ops.mesh.remove_doubles(), which merges vertices by distance using the default threshold.

Adding Properties for the Tweak Popup

To make the tweak popup work, we need to define properties that can be adjusted in the popup. For the merge vertices operation, the most important property is the merge distance.

    threshold : bpy.props.FloatProperty(name="Merge Distance", default=0.0001)

    def execute(self, context):
        bpy.ops.mesh.remove_doubles(threshold=self.threshold)
        return {'FINISHED'}

Here, we add a FloatProperty named threshold with a default value of 0.0001. In the execute function, we now pass threshold=self.threshold to bpy.ops.mesh.remove_doubles(), so the merge operation uses the value set in the popup.

Putting It All Together

Here’s the complete code for the operator:

import bpy

class MergeVerticesOperator(bpy.types.Operator):
    bl_idname = "mesh.merge_vertices_by_distance_tweak"
    bl_label = "Merge Vertices"
    bl_options = {'REGISTER', 'UNDO'}

    threshold : bpy.props.FloatProperty(name="Merge Distance", default=0.0001)

    def execute(self, context):
        bpy.ops.mesh.remove_doubles(threshold=self.threshold)
        return {'FINISHED'}

    def invoke(self, context, event):
        if event.ctrl:
            return context.window_manager.invoke_props_dialog(self)
        else:
            bpy.ops.mesh.remove_doubles()
            return {'FINISHED'}


def register():
    bpy.utils.register_class(MergeVerticesOperator)

def unregister():
    bpy.utils.unregister_class(MergeVerticesOperator)

if __name__ == "__main__":
    register()

Registering the Operator

To use the operator in Blender, you need to register it. The register and unregister functions handle this. When you run the script, register() is called, which tells Blender about your new operator. If you need to remove the operator (e.g., when updating your script), you can call unregister().

Adding the Operator to a Panel

Creating the operator is just the first step. To make it accessible, you’ll likely want to add it to a panel in the Blender UI. Let’s create a simple panel and add a button that calls our operator.

Creating a Custom Panel

First, define a panel class that inherits from bpy.types.Panel:

class MyCustomPanel(bpy.types.Panel):
    bl_label = "My Custom Tools" # Panel name
    bl_idname = "VIEW3D_PT_my_custom_tools" # Unique identifier
    bl_space_type = 'VIEW_3D' # Display in 3D Viewport
    bl_region_type = 'UI' # Display in the UI region
    bl_category = "My Tools" # Sidebar tab name

    def draw(self, context):
        layout = self.layout
        row = layout.row()
        row.operator("mesh.merge_vertices_by_distance_tweak") # Add the operator button


def register():
    bpy.utils.register_class(MergeVerticesOperator)
    bpy.utils.register_class(MyCustomPanel)

def unregister():
    bpy.utils.unregister_class(MergeVerticesOperator)
    bpy.utils.unregister_class(MyCustomPanel)
  • bl_label: The name of the panel displayed in the UI.
  • bl_idname: A unique identifier for the panel.
  • bl_space_type: The area where the panel will appear (e.g., 'VIEW_3D' for the 3D Viewport).
  • bl_region_type: The region within the area (e.g., 'UI' for the sidebar).
  • bl_category: The tab in the sidebar where the panel will be located.
  • draw(self, context): This function is called to draw the contents of the panel. Here, we add a button for our operator using layout.operator().

Registering the Panel

Just like with operators, you need to register the panel. We’ve already updated the register and unregister functions to include the panel class.

    bpy.utils.register_class(MergeVerticesOperator)
    bpy.utils.register_class(MyCustomPanel)

Now, when you run the script and go to the 3D Viewport’s sidebar under the “My Tools” tab, you’ll see the “My Custom Tools” panel with a “Merge Vertices” button. Clicking the button will merge vertices, and CTRL-clicking will bring up the tweak popup.

Troubleshooting Common Issues

Creating custom operators can sometimes be tricky. Here are a few common issues and how to troubleshoot them:

  • Operator Not Found: Double-check the bl_idname. It needs to be unique and correctly referenced in your panel or menu.
  • Popup Not Showing: Make sure the invoke function is correctly checking for the CTRL key and calling invoke_props_dialog().
  • Properties Not Updating: Ensure your properties are defined correctly and passed to the operator function.
  • Blender Crashing: This usually indicates a bug in your code. Use Blender’s console (Window > Toggle System Console) to check for error messages.

Conclusion

Creating custom operators with tweak popup windows in Blender using Python is a powerful way to enhance your workflow. By handling different actions based on key presses like CTRL, you can create more intuitive and efficient tools. We’ve covered the basics of operator structure, handling events with invoke, adding properties for tweak popups, and integrating operators into panels. Now it’s your turn to experiment and create your own awesome tools! Happy blending, guys!

SEO Keywords

  • Blender Python
  • Custom Operators
  • Tweak Popup
  • Merge Vertices
  • Blender Scripting
  • Python Scripting
  • Blender Addons
  • Python for Blender
  • Blender Development
  • Blender Tools