API

How to calculate the Bounding Sphere for selected objects

Most often, for quick simplified calculations with the object’s geometry, their Bounding Boxes are used – the minimum parallelepiped into which this object is inscribed. But sometimes the Bounding Sphere – the minimum sphere into which an object can be inscribed – can provide greater accuracy and simplify the calculations. While the location and size of the object’s Bounding Box is available in Blender at once, the Bounding Sphere we need to calculate manually

Let’s write a function that, based on the object list, returns the coordinates of the center of their Bounding Sphere and its radius.

Multiline text in Blender interface panels

Unfortunately, Blender’s interface does not support word wrapping and multi-line text blocks. Text lines that are too long to be displayed in the panel are cut off. However, multiline text can still be displayed on the panel using several text elements instead of one.

First, let’s create a simple panel in the N-panel of the 3D Viewport window and place a label element with the desired text on it.

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:

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.

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.