By default, when drawing with a drawing guide active, your mouse cursor will lock against one of your guide's axes, forcing it to draw along the axis as if you were drawing against a ruler.
If you want, you can disable this behaviour by turning off the 
Align with Guide option, and only use your drawing guide as a visual reference. This can be useful if you want to draw with less rigid drawing style.
When the Align with Guide option is disabled:
- Your drawing tool will allow you to draw in any direction.
- The guide will still be visible, but will only serve as a visual aid.
- While drawing, the dotted line representing the axis you are drawing along will lock into place instead of following your mouse cursor, so that you can follow it as you draw.
How to draw freehand perspective
- In the Guides view, click on the Align with Guide button to toggle it off
-
Start drawing.
