when make offset path, I put minus numbers (-1,-10) but made 2lines both inside and outside.

[ARA3196541486yw]

Everytime I make offset path, 2 lines have been made both inside and outside.

whatever I put minus or plus numbers. How can I solve this problem?

Red lines in the attachment are the lines made by offset path function.

Thanks, 

[Bobby Henderson]

It looks like you're applying the Offset Path effect to an open path rather than one that is fully closed. If you apply the Offset Path effect to a closed path a postive number value will create a new path outside the source path. A negative value creates a path inside the source path.

[Jacob Bugge]

ARA,

In addition to what Bobby said, your second attachment shows a (closed path) rectangle at the bottom right and an open path that starts (or ends) at the upper right corner of the rectangle, goes up, then to the left, then down again, thus appearing as an extension to the rectangle below, then continues from the left the upper leftt corner of the rectangle.

This open path is above the rectangle in the stacking order, as you can see in the (expanded) Layer in the Layers panel.

There is no real inside or outside of an open path in the way that you see it, so Illy (job description Adobe Illustratir) kindly gives you the nearest you can get to it: a closed path surrounding your open one.

This closed red path is between the original open black one and the rectangle in the stacking order, as you can see in the (expanded) Layer in the Layers panel: it shows on top of the rectangle but beneath the end path segment of the open black path, which obviously has Butt Cap so you see the lower half of the width of the red path there.

Judging by the Heading (when make offset path, I put minus numbers (-1,-10) but made 2lines both inside and outside.), you wish to have a red path follow the original black path on the side that appears to be the inside, you can:

1) With everything deselected (you can Click an empty spot on the Artboard), Click the horizontal bottom segment of the red path at the open end Anchor Point of the original open path with the Direct Selection Tool and delete it, then deselect it, then repeat for the other open end Anchor Point; if you fail to deselect in both cases, you will delete all of the red path(s);

2) Click the unwanted red path that appears to be on the outside and delete it; this ought to leave you with an open red path following original open black one on the inside, but its bottom end will look funny because it will cover half the stroke of the rectangle, hence the next step;

3) With the the bottom end Anchor Point of the vertical segment of the red path selected with the Direct Selection Tool, open Object>Transform>Move and insert half the value of the Stroke Weight in the Vertical box and press Enter; this will move its end down so it covers the horizontal segment of the rectangle; if you wish it to be flush with the upper side instead, use the same negative value.

[Jacob Bugge]

ARA,

On the other hand, if you wish to have the red path appear to be outside/above the original black open path and have it appear to be closed at the bottom right flush with the outer side of the rectangle, you can:

1) Click the leftmost Anchor Point of the horizontal bottom segment of the red path at the open end Anchor Point of the original open path with the Scissors Tool, then deselect and delete the end segment at the other end and deselect again as in 1);

2) Click the unwanted red path that appears to be the inner path and delete it;

3) Click leftmost end Anchor Point of the horizontal bottom segment of the red path from 1) with the Direct Selection Tool, then open Object>Transform>Move and insert the (positive) Offset + half the Stroke Weight in the Horizontal box (you can just insert both the values with the plus between them and let Illy calculate it for you) and press Enter; this will move its end to be flush with the outer side of the vertical segment of the rectangle.