Finding a point on a line to start from

[jgratton]

After reading help, downloading ATPs etc, I STILL can't find out how to begin a line from a point 1000 units along the x plane from the circle, as shown in the provided picture.

I don't want to cheat by offsetting or draing a temporary line that needs to be later erased.

What am I doing wrong?

So far I have typed:

Command: line
Specify first point: .yz
of cen of (need X): @1000<180

I also tried
of (need X): 1000<180

I can't find a way to grab that point by using the keyboard. And that is the way I want to do it.

I have been warned by others not to use osnap tracking or dynamic input for 3d, and I have noticed that lines, 2d polylines and 3d polylines all have different strengths and weaknesses in 3d.

I want to understand the command line syntax of AutoCAD the way one would learn a second language. Any insight into this is appreciated.

[jaberwok]

Hi Janet.
First, creating construction geometry is NOT cheating.

However, the simplest way that doesn't require any temporary geometry is to draw the line from the centre of the circle then move it by 1000 in -x.

Otherwise offset the circle to create an intersection or use Measure to place a Point (node) on the line (points can be made invisible so you don't have to erase them (and many people don't erase them). Or, of course, just draw a line from the start @-1000 and then draw the line you want and erase the first line.
BTW, I've found that my remark about polyline vertices is no longer relevant as Line now seems to work the same way as Pline (I wonder when that was changed).

[fhoffnar]

I agree with jaberwok.. construction lines (not XLINE) are your life blood. I easily draw 3x as many construction lines as real objects, they help visualize and define the problem.

[tedg]

I agree with jaberwok.. construction lines (not XLINE) are your life blood. I easily draw 3x as many construction lines as real objects, they help visualize and define the problem.
Hi guys, what do you mean by "construction" lines?
I use xlines allot for projecting points etc. and then trim them into lines if I need them.
Is there something else?

[fhoffnar]

Construction lines define key geometry in a design. For example the sweep of an arc, or a center point of a hole. This can also be temporary geometry that the drafter or designer can use to build the drawing.

AutoCad calls the XLINE command 'construction line', which is a confusing name for a command of limited function.

[jaberwok]

To me, construction lines are anything that I draw knowing that I will erase them later.

[tedg]

Construction lines define key geometry in a design. For example the sweep of an arc, or a center point of a hole. This can also be temporary geometry that the drafter or designer can use to build the drawing.

AutoCad calls the XLINE command 'construction line', which is a confusing name for a command of limited function.


To me, construction lines are anything that I draw knowing that I will erase them later.
Ok then, that's what I thought.
I come from the "board drafting days" where we drew construction lines to build the drawing on. It was usually a real light line or "blue line" so the Diazo machine didn't pick it up.

If I'm doing construction lines in AutoCAD that I plan on erasing, I usually use layer zero with an obnoxious color so I don't forget to delete it. I use xlines allot for construction lines when I need to project a point. Or I'll use regular geometry like lines circles etc. trim them and put them on the correct layer. If I use construction lines that I want to keep for reference but not plot, I put them on a "no plot" layer with a wierd color too.

I was only asking because I didn't know if you meant something else that I didn't know about.

Thanks

[ward423613]

I've used both object snap tracking and running object snaps in 3D with excellent results. I wonder why you were warned off of these tools? Regardless the keyboard method you're after here is the Osnap FROM.

Command: LINE
Specify first point: FROM
Base point: CEN
<Offest>: @1000<180 (start point of your line)
Specify next point: (and so on)

[jgratton]

I've used both object snap tracking and running object snaps in 3D with excellent results. I wonder why you were warned off of these tools? Regardless the keyboard method you're after here is the Osnap FROM.

Command: LINE
Specify first point: FROM
Base point: CEN
<Offest>: @1000<180 (start point of your line)
Specify next point: (and so on)

Eureka! That's exactly what I was after. Thanks :)