Intersection Relation
The Intersection relation puts a point exactly where two pieces cross, and keeps it there as they move. The pieces can be lines, circles, arcs, or a straight edge of the part.
When to Use It
- Hold a hole center where two construction lines cross
- Start a line where a circle crosses another line
- Keep a point on the crossing of two walls in a floor plan as they move
Step by Step
- Open a sketch and draw the pieces (see Lines, Circles and Rectangles). Sketching is part of modeling, which comes with the Pro plans.
- Click Select on the Sketch tab (or press S).
- Move the pointer over the piece that owns the point until its dots show, and click the point (an end, a corner, or a center).
- Click the first of the two pieces, then the second. On a rectangle or outline, click the side you mean.
- Keep the pointer still for about half a second. In the bar that opens, click Intersection. You can also click it under Add a relation in the Properties panel.
- The point moves to the crossing and a message says Intersection added: ... now sits where ... cross, and stays there as they move. Ctrl+Z takes it back.
Options
| Setting | What it does |
|---|---|
| Two lines | A line counts as running on past its ends, so two lines that would meet if drawn longer have a crossing. |
| A line and a circle, or two rounds | They cross in up to two places. The point goes to the crossing nearest to where it is now. An arc counts as its whole circle. |
| A part edge | A straight edge of the part can be one of the two. It joins the sketch as a gray reference and never moves. |
| Which one gives | The pieces stay and the point moves to them. If the point is held (Fixed, or tied to the part) the pieces move to it instead. |
| Afterward | Move either piece and the point follows the crossing. |
Tips
- To choose between two crossings, drag the point near the one you want before you add the relation.
- The point must belong to a third piece, not to either of the two it sits on.
- When the point is an end of an arc, the whole arc moves at first to bring it to the crossing, then reshapes as its other relations allow.
- A point that is already an end of one of the two pieces is on it already. Use Coincident Relation to put it on the other piece.
- One Ctrl+Z takes the relation back.
If Something Goes Wrong
- "... are parallel, so they never cross. Turn one of them, or pick two that cross." Two parallel lines have no crossing.
- "... lie on each other, so there is no single place where they cross." The two lines are on one line, or the two rounds are one circle.
- "... do not cross as drawn, so there is no crossing for the point. Move one until they cross, then try again." A line that passes clear of a circle, or two circles apart, do not meet.
- "... is on ... already, so it cannot be put where ... crosses another piece." Pick a point of another piece.
- "... belongs to ..., one of the two pieces it would sit on." The point is a corner, end or center of one of the two pieces you picked. Pick a point of a third piece, or use Coincident.
- "Intersection needs two different pieces to cross." Two sides of one rectangle were picked; pick two separate pieces.
- "Intersection cannot hold together with the relations already there. Nothing changed." Something already placed fights it. Delete the one in the way from the list under Edit.
- The button is not in the bar. Intersection needs exactly one point and two lines, circles or arcs. A spline cannot be one of them.