If you're about to place leaves or other random stuff without a particle system and want to quickly alter their rotation, just hit R twice and you can nicely rotate the object trackball-like. When you're figuring out contours between two colours, this is especially useful and speeds up your work. This lets you switch between the two active colours in Texture or Vertex Paint Mode, just like in Photoshop. This is very useful for cleaning up UV coordinates.

Further unwraps will then consider their position. When you're in UV Edit Mode, you can pin certain vertices to let them be fixed if you unwrap the model again. Especially when you're dealing with cylindrical objects, this comes in handy by being able to let you 'wander' the selection across the model. This enables you to grow (+) or shrink (-) the current face selection radially in all directions. This is very useful when you want to quickly isolate certain parts of the mesh for selective unwrapping or assigning vertex colours. Turns the cursor into a circle brush that lets you 'paint' a selection of faces, vertices or edges.

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