When you duplicate an object in Blender (e.g., using Shift + D), Blender creates a new, independent copy of that object. While this seems straightforward, it comes with some performance implications:

1. Memory Usage
   Each duplicated object stores its own data for vertices, faces, and materials, consuming additional memory.

2. Computational Overhead
   Blender must process and manage every individual object and its data, which increases CPU and GPU workloads.

3. File Size Growth
   Duplicating objects bloats the .blend file, leading to longer save/load times and slower operations.

In contrast, Object Instances allow you to reuse the same object data multiple times without duplicating it. This keeps the scene lightweight and optimized.

An instance is a reference to the original object, not a copy. Instead of duplicating the geometry, Blender reuses the same data for each instance. This drastically reduces memory usage and speeds up rendering and viewport performance. Additional benefits:

• Reduced Memory Usage: Only the original object data is stored.
• Faster Viewport Performance: Blender handles fewer unique objects.
• Smaller File Sizes: Instanced objects don’t add significant data to the .blend file

1. How to duplicate as an Instance

Instead of duplicating objects with Shift + D, use Alt + D to create an instance:

1. Select the object you want to duplicate.
2. Press Alt + D and move the instance to a new location.
3. Notice that any changes to the original object’s geometry (edit mode) are reflected in the instances.