When we ctrl+drag an object from the content library, add a "brush here" function to the pop up menu. This will turn the cursor into a brush so that we can paint that object where we brush it. A floating help menu comes up with modifiers we can use to change the brush. For example, ctrl+drag up and ctrl+drag down increases or decreases brush size, alt+drag up and alt+drag down increases or decreases painting density, shift+paint deletes what we painted. By default, the brush will not paint over...