Stupid NOOB question

 From:  Michael Gibson
3201.2 In reply to 3201.1 
Hi John,

> I was wondering if there is a keystroke to constrain
> drawing a line segment perpendicular to teh workplane.

You mean while drawing in the 3D view?

Make sure you enable Straight Snap in the bottom toolbar here:

When that is enabled (it has that orange highlight when enabled), you can get a line that snaps to the x and y axes when in the 2D views, and it will also snap to the z axis in the 3D view as well.

You don't need to press any key to use it, you just move your mouse close to the line and it will snap there, and it will show a label at the base point for which direction it is snapping on to.

Here is an example:

So note there that I just move the mouse close to one of those directions to lock on to it, you don't need to hold down any keys while doing that. When it says "z" at the base point, that is the one going perpendicular to the construction plane like you are asking about.

If you want to just place one point elevated up and not the whole line perpendicular, then you can use a construction line for that - to create a construction line you click and hold down and drag away from a point rather than click and release. That pulls out a construction line that can be used for all kinds of alignment, extensions, elevations, etc... Here's an example of doing that while placing the endpoint of a cylinder directly elevated above the end of another line in the xy plane.

That again does not need a keystroke to enable it, instead it is triggered off of that "hold down and drag" motion with the mouse.

Check out the video tutorials for more details on construction lines, they are covered in a couple of them:

And also a reference page is available here that goes over the many uses of construction lines:

Construction lines replace a whole chunk of what are often separate individual mechanisms in other programs, things like "elevator mode", extension lines, getting the point midway (or at 1/3 or 1/5 or whatever intervals) between 2 existing points, and more...

- Michael