Custom panel

Today’s goal

My goal: by the end of the day, I want to create such a panel with buttons, sliders… to manipulate the view.

The process

I have no step-by-step plan, but I know what I want to achieve at the end of the day, so I will research first. And I now want to start keeping the blog one step at a time so I don’t have to do everything at once.

Let’s start!

Research

After looking up some articles & videos, I am going to check them out and possibly try to join in. While doing that, I will take some notes of things I have learnt.

I found some aritcles that explains the basics of creating your own custom panels & making them as add-ons so you can use them in any blender project. There are several steps in creating a custom basic panel, but I am happy to refer here to the well-documented sources I used for this.

• Article (https://community.osarch.org/discussion/759/blender-create-your-first-blender-add-on) starts from the template “UI Panel Simple”
• Victor Stepanov (https://www.youtube.com/watch?v=Qyy_6N3JV3k&list=PLB8-FQgROBmlqzZ4HBzIAGpho-xp0Bn_h&index=2) explains in his videos very well how to work with Blender’s Python API from scratch.

Learning 01: there are several python templates in blender.

Scripting > Templates > Python > …

Basic panel

A panel consists of operators, you can compare it to functions, they do something, they perform an action. Important to know is that they work on the active object & a correct context is needed.

Step by step: create a basic panel

0. Create panel class
1. Panel location
2. Labels
3. Layout
4. Register & unregister panel
5. Add-on

0. Create panel class

class CATEGORY_PT_name_of_your_panel(bpy.types.Panel): # naming convention for panels

1. Panel location

Where will the panel be placed in the UI of Blender? Use bl_space_type & bl_region_type.

bl_space_type
This is the “big location” where our panel will be located. There are different types. You can see this by clicking on a space icon.

bl_region_type

2. Labels

Give your panel a name -> use bl_label.

3. Layout

-> Inside draw() function: create rows (or columns) with operators.

    def draw(self, context):
        layout = self.layout

        row = layout.row()
        row.operator("mesh.primitive_cube_add", text="Add cube") # creates a cube when clicking on the Add cube btn

4. Register & unregister panel

Let Blender know the panel exist.

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

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

    if __name__ == "__main__":
        register()

5. Add-on

5.1. Preparation step

• (!) unregister
• add bl_info dictionary

5.2. Save add-on Inside text editor: Text > Save As (!) .py extension, so Blender recognizes the add-on.

5.3. Add add-on in Blender

• Restart Blender
• Edit > Preferences > Add-ons > Install from disk
• Enable your add-on (check checkbox)
• You see your add-on in your project

Learning 02: To know the correct name - click on an item and see it appear at the bottom left.

Explore further

Let’s create a panel with different UI elements with built-in operators (like when clicking on button, you add a cube). But first, what are the different options we have? Can we use a text input, checkbox, slider…?

Let’s experiment with a cube and the different options we can find in the documentation (https://docs.blender.org/manual/en/latest/interface/controls/index.html#ui-elements).

This is my status at the moment:

I created sub panels by using bl_parent_id, added a checkbox, radio buttons (https://blender.stackexchange.com/questions/30421/create-a-radio-button-via-python), changed default text…

I don’t quite get my way around the documentation yet and also find it difficult to quickly find, for example, how to link a built-in operator to a checkbox.

Next steps

My steps were:

1. Find tutorials on the topic
2. Try to understand tutorials and write things down
3. Explore different UI elements

The next steps are:

1. Understanding operators better - how are they created, can I create a custom operator?
2. Try other UI elements, that I haven’t implemented yet, like a color field, text input field… The steps above I want to focus on learning and just changing a basic shape (like cube) (i.e. as I am doing).
3. Try to modify a rhombohedron fractal in a custom panel with the things I have already learned.

Reflection

I found it easier to work with a specific goal in mind. Although my daily goal could be formulated smaller, my next steps are already clear. I hope to be able to modify my rhombohedron fractal a bit by Sunday evening.