Extend projected line

[ltomuta]

Looks like if I project a line (and keep it linked) I cannot use the Modify -> Extend command unless I first delete the projection constraint. Why so?

The intent is clear, I want a line segment to be added to the end of my projected line and that segment should have a colinear constraint linking it to the projection. It does not need to alter the projected line in any way so it remains "uneditable".

[mango.freund]

hello, but that's logical. these lines replace important information such as location, length and distance, space and time. so if you want to change these lines then change the body from which it originates. It's not called projection for nothing. loosen means that your new part cannot travel with you when your other part changes. The only good thing is that there are no error messages.

[TheCADWhisperer]

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@ltomuta wrote:

The intent is clear, I want a line segment to be added to the end of my projected line and that segment should have a colinear constraint linking it to the projection. It does not need to alter the projected line in any way…

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With that clear intent I would use the Line command.

Can you File>Export your *.f3d file to your local drive and then Attach it here to a Reply?

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[ltomuta]

The advantage of Extend is that it not only determines the correct direction but also stops at the next "projected" intersection. I can do the same thing with a line and a couple of explicit constraints but that amounts to a few extra clicks.

I hate clicking. 🙂

[JDMather]

You didn’t Attach your file here?

I prefer robust designs that are easy to edit and easy to repair when things go wrong. 
I seldom use Projected lines for geometry that might change going forward.

Instead I convert the Projected geometry to Construction and the sketch my profile object line overtop of the construction geometry Projected line.  My line can be extended/trimmed/dimensioned as needed.

If for some reason the Projected construction reference “goes sick” it is easy to delete and repair whiteout my entire design indicating yellow and red issues in the Timeline.  Get lazy!

[mango.freund]

hello, actually i saw this question answered.
but there are still treatment problems.
I would solve your problem with another advantage as follows:
1. draw a second line and make it DETERMINE A DISTANCE TO THE PROJECTED LINE or colinear as mentioned.
2. extend this line with your desired comfort.
greetings

[mango.freund]

hello @JDMather --- Your explanation is plausible, but ignores the parameterization which takes place automatically with configured elements. i love to use pink lines to develop my drawings easily and without dimensioning. how simple if only changes to the projected body have to be dimensioned.    

the alarm messages are very important when you work on very wide / long bodies and a quick click every distance as a laser burns on my sketch and cannot be changed.

greetings mango

[ltomuta]

I did not post a design file because the particular geometry does not mater.

I mainly need quick sketches to tweak some toolpaths in CAM side of things so I'm dealing with designs that never change (if they do I receive another step file from customer and program that one for machining) unless I mess something up. So I't rather project and extend instead of drawing lines for point A to point B.

What I need is simple lines that stay true to the design (therefore projections) with little tweaks (gaps filled, edges bridged ...) 

Let's take this body. The silver edges are projections. The question is: what is the damage that could possibly be done if with four clicks I would "extend" them all until the circle is complete and the two edges on the right unite in a vertex?

It is not a question if I can do it with lines or arcs with or without explicit constraints. Obviously I can. But with more clicks and more error prone (it does not take much for two vertexes that appear collinear not to be).

[JacobBZRLE]

I came searching for an answer to this. Dealing with exactly the issue described here. Need to connect some edges (that are intersected by other geometry) for CAM programming. Wish it was possible to extend projected lines without breaking the projected link. Your example above illustrates the issue perfectly. It becomes even more complicated to manually draw new connecting elements as the part complexity increases.

Addressing one of the replies above: Just because the endpoints change doesn't mean the projected geometry would not be able to travel with the base geometry if changes were made. Just look to SW, Inventor, NX, or really any other professional CAD software to see how this can work and benefit the user.