Remember, each Canvas has its own Canvas Renderer component. Canvases combine all their elements into batches that are rendered together. A Canvas is considered dirty, if its geometry needs to be rebuilt. One of the main goals of optimizing UI is to reduce the number of times a Canvas or its elements are considered dirty, to reduce the number of times that the Canvas needs to be rebatched. With that in mind, let’s look at some techniques for optimizing Unity UI.

Using multiple Canvases and Canvas Hierarchies

Whenever an element on a Canvas is modified, the Canvas is considered dirty, and a draw call is sent to the GPU. If there are multiple items on the Canvas, all the items on the Canvas will need to be reanalyzed to determine how best they should be drawn. So, changing one element on the Canvas requires the CPU to rebuild every element on the Canvas, potentially causing a sudden surge in CPU usage. Due to this, you should put your...