Features of using the scale matrix

To manipulate object transformations with matrices, Blender includes the “mathutils” module in which the “Matrix” class is defined. With this class, you can simply create the necessary transformation matrices – translation, rotation, and scale.

The following command is used to create a scale matrix:

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Localization of Blender add-ons – with API

The classic way of localizing a Blender add-on (translating it into different languages) is convenient because requires just a single Blender Python API call – to get the currently used locale. This way is maximum universal, but Blender would not be Blender if it did not provide users an ability to localize add-ons through its own API.

The principle of creating multilingual add-ons using the Blender Python API is not much different from the classical one – we need to create a dictionary with all the variants of translations for all text strings from our add-on and use this dictionary in the localization.

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How to get mesh data with modifiers

When referring to the mesh geometry – its vertices, edges, and polygons, Blender operates with the original data without the usage of modifiers added to the object.

For example, the number of vertices of the active object, we can get with the following command:

And it will be returned without considering the object’s Subdivision modifier, which modifies the mesh’s geometry, increasing it.

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How to make an url button in Blender interface

In order to navigate to an URL-address from Blender – to open the required address in the browser, we can use the system operator “wm.url_open”.

To demonstrate this let’s create a simple tab in the N-panel with a single button, by clicking on which the required page will be opened in the browser.

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How to get scene data from the bpy.context

To have the access to the current context, for example, to work with operators, and to the scene data, for example, to work with meshes, we use two predefined structures from the Blender Python API: “bpy.context” and “bpy.data”.

For example, we can pass them to a function:

However, in the “bpy.context” structure there is a “blend_data” pointer that links to the scene data. With this pointer, we can access scene data without passing it separately and explicitly.

Localization of Blender add-ons – classical way

If you want your add-on to be available for all Blender users around the world, you need to make the localization – translation of its interface into different languages.

The simplest way to make your add-on multilingual is the classic way, it is used in many other programs and requires the minimal usage of the Blender Python API.

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Removing collections through the Blender Python API

We can delete collections in Blender through the “collections” list in “bpy.data”.

To remove a collection we need to use the “remove” method from the collections list, specifying the collection to be removed in the parameter:

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How to add a constraint to the object with Blender Python API

We can assign constraints to objects through the object “constraints” property.

To add a constraint to the currently active object, we need to create a new constraint in the object’s “constraints” list, specifying its type in the parameters:

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Deselect all with a single pressing of the “a” keycode

Since Blender 2.80 the deselect all function – complete deselection of all objects or geometry – has been switched from a single press of the “a” key to a double “a-a” or a combination of “alt+a” keycodes. To return the deselection function to a single “a” press, we can edit the settings of the selection operators. Or, since Blender 2.81, a special checkbox is provided for this in the keyboard shortcuts settings.

  • Open the “Preferences” window
  • Switch to the “KeyMap” section
  • Turn on the “Select All Toggles” checkbox in the “Preferences” subsection
  • Save the settings by pressing the “Save Preferences” button in the upper right corner of the window.

Now the selection of all objects/geometry and their total deselection will be performed by pressing the single “a” key.