Extending lines within a shape

Here's my 2¢ on it. If the shapes are rectangles with radius curve corners and it's just the straight line segments that need to be extended outward, possibly intersecting across each other at the corners, I would handle it like this:

Break open the anchor points on the rectangle using the Scissors tool. Then select the straight line segments with the Selection tool and just resize them horizontally or vertically. Resizing works on diagonal straight line paths by holding down the shift key to constrain proportions.

If the rectangle is a live shape the Direct Selection tool will have to be used to select some of the anchor points on the path to split open with the Scissors tool. Then the remaining points can be selected and split.

If any paths that need to be extended have any curving features those would be handled best by a third party plugin, such as Astute Graphics' VectorScribe plugin. That plugin has an Extend Path tool that works pretty well on both straight and curved paths.

siderealxxx,

Based on the (mis)understanding that you wish to keep the current side angles and corner roundings just as they are, all the new relative sizes and proportions will become different to the old ones, requiring a customized.stepwise approach.

If you wish to extend both straight sides upwards or downwards or from the middle by a specific vertical or horizontal amount, you can, Smart Guides being your friends:

1 ) Expand if the shape is a live shape so you fix the corner roundings between Anchor Pointsconnecting them to the straight sides;

2 ) Deselect everything, then with the Direct Selection Tool click either straight side segment and copy it, then in the Transform palette click the relevant Reference Point, then change the W or H value as desired and lock it; then is a separate straight guide path

3 ) Repeat 2 ) for the other straight side segment;

4 ) DirectSelect the set of Anchor Points in one of the corners (you can ClickDrag over them), then ClickDrag by the relevant Anchor Point to snap it to the end of the guide path;

5 ) Repeat 4 ) for the other three corners;

6 ) Hide/delete the guide paths.

I believe this may be one of the ways that Kurt referred to.

Thanks, I’ll try these options asap! 

There are some more ways, depending on what you actually have. For example:

If your rectangle is a live shape you may just change its width or height in the Transform panel numerically.

If the bounding box of the rotated rectangle is not reset, you may use this bounding box to scale it manually, retaining the actual angle.

You may also direct select one or several anchor points and use the Move dialog where you can set the appropriate distance and angle.

Hi ​@siderealxxx,

I would go about this by turning on Smart Guides (command + U), Preview (command + Y), and then while using the white arrow (direct selection tool) (A), select the node you’d like to extend and drag it outwards. You’ll see it says “line extension” and snaps to the proper angle/position while allowing you to extend the path.