Okay, sketching lines may not seem like a particularly advanced trick, but there are a few subtle things you can do while sketching a line that can change the behaviour. You are probably already aware that you can create a single line using the click & drag method or multiple lines using the click-click method. Both are described in this blog article if you are not already familiar with it. Something that is less well known is that if you are sketching something, you can use the Ctrl or Shift keys to change how SOLIDWORKS handles this.
For instance, this is a screenshot of me drawing a regular line:
Nothing particularly special about that method. You will notice that it displays the length and angle of the line, as well as a yellow Horizontal sketch relation, indicating that if I place the other end of my line here, it will get a sketch relation.
Automatic Relations System Option
However, what if I don’t want that sketch relation to be automatically added. Sure, I can adjust my system settings (Tools > Options, under System Options, Sketch, pick Relations/Snaps from the list and uncheck Automatic Relations), but I’ve already started my line and do not wish to be interrupted.
Sketching with Ctrl key
Of course, since I don’t want to go through all that just for this one line, and have to change it back again afterwards; I’m going to use a trick: Hold down the Ctrl key when selecting the second point of the line. Result: No automatic sketch relation. So simple and quick. Go ahead and try it yourself right now and see how easy it is!
Now generally when there’s a quick trick like this involving Ctrl, Shift, or Alt, there’s another quick trick for the other keys. For the time being (SOLIDWORKS 2016 SP1), it is unclear what, if anything, Alt is supposed to do (likely reserved for some future functionality, so think up some enhancement requests and send them in to SOLIDWORKS).
Sketching with Shift key
As for Shift, if we hold it down while sketching lines, it tends to snap to the grid. The Grid settings can be found in the Document Properties (under Grid/Snap) and for mine, it is set as 100mm for Major Grid Spacing, and 10 minor-lines per major, meaning it should snap every 10mm. Behold:
Keep in mind that this doesn’t apply to every kind of sketch relation or dimension (unless I have automatic dimensioning turned on), so it will not define my sketch, but it makes it easier to sketch things to an exact length.
You can also use these methods for other sketch entities. Shift works for Lines, Rectangles (just not Corner or Centre rectangles) Circles, Slots (the centreline of the slot, anyways), and Polygons. Ctrl works for anything that would make a sketch relation.
It is also worth pointing out that you can use Ctrl while dragging in order to drag, say, a line’s endpoint onto another line does not apply a sketch relation, provided that you don’t press Ctrl until you are already dragging the endpoint.