> ## Documentation Index > Fetch the complete documentation index at: https://docs.redbrickai.com/llms.txt > Use this file to discover all available pages before exploring further. # Instance vs. Semantic **Semantic segmentation** treats multiple objects of the same class as a single entity. In the example below, you can see that the labeler is responsible for annotating a single structure ("Vertebrae"), regardless of the vertebrae's classification (e.g. L1, S1, etc.).

On the other hand, **instance segmentation** treats multiple objects of the same class as distinct individual objects (or instances). In the example below, the annotator must create a unique annotation (as represented by an Instance in RedBrick AI) for each specific vertebrae.

On RedBrick AI, you can **perform both semantic and instance segmentation** by controlling how many instances of a particular category you create on the left side bar. If you create more than one instance of a single category, on export, you will be able to correlate the instance IDs in your segmentation mask to your category names. Check out this video for an overview: