When you want to create features, you'll most commonly use the Create Features window's construction tools and the construction methods on the Editor toolbar. With those tools, for example, you can create lines, arcs, tangent curves, vertices at intersections or midpoints, vertices based on distances and directions from other features, or new segments by tracing along existing ones.
By default, the Line and Polygon tools create straight segments between the vertices you click. These tools have additional ways to define a feature's shape, such as creating curved lines or tracing existing features. These are construction methods, which are located on the Editor toolbar. To create a curved segment, click that construction type from the palette on the Editor toolbar and draw the curve on the map. You can even switch among construction types after each segment, allowing you to build the exact shape you want. For example, if you are drawing a road with a bend in it, you may want some of it to be straight and some to be curved. To do this, start with Straight Segment, digitize the straight segment, then click a curved segment construction method and create the curve.
To access the feature construction methods, you can use either the Editor toolbar or the Feature Construction mini toolbar.
Each time you click the map with a sketch tool used to create segments, such as the Line or Polygon tool, the Feature Construction toolbar appears. The toolbar provides a shortcut to the segment construction methods on the Editor toolbar, so you can create straight or curved segments and easily access any of the other construction methods. As you click the map, the Feature Construction toolbar follows your clicks.
If you want the Feature Construction toolbar to appear anytime you are sketching, you need to enable it on the Editing Options dialog box. Click the Editor menu and click Options. On the General tab, check Show feature construction toolbar.
If you want to display the Feature Construction toolbar only when you need it, you can press the TAB key to show it temporarily. For example, to create a parallel segment, press the TAB to display the Feature Construction toolbar, click Constrain Parallel, and close it or press TAB again to hide the toolbar.
Below are the available construction methods.
Straight
Straight Segment 
is the default method to digitize the vertices of line or polygon features. A vertex is placed each time you click, with the segments between vertices being straight lines.
Arc
Arc 
helps you create a segment that is a parametric (true) curve. Instead of being made of numerous vertices, a parametric curve has only two vertices as endpoints. You might use Arc to digitize a cul-de-sac, using an aerial photo image as a backdrop.
Bézier
Bézier 
constructs smoothed curves. You can use the handles to change the angle, height, and shape of the curve. If you rotate the handles, you can create an S-shaped curve.
Direction-Distance
Direction-Distance 
allows you to create a point or vertex using a distance from a known point plus a direction from a known point to define a bearing line. For example, a pole might be located at a specified distance from the corner of one building and at a defined angle from the corner of another building.
Distance-Distance
Distance-Distance 
allows you to create a point or vertex at the intersection of two distances from two other points. For example, the Distance-Distance method could be used to place a new electrical pole based on field measurements. The next point is known to be 50 feet from one building corner and 75 feet from another. Distance-Distance creates two circles based on these distances and finds two possible intersection points where the pole can be placed.
Endpoint Arc
Endpoint Arc 
allows you to specify the start and endpoints of the curve, then define a radius for the curve. This is particularly useful in sketching culs-de-sac, where the beginning and ending points of the arc, as well as the radius of the cul-de-sac, are known.
Intersection
Intersection 
creates a point or vertex at the place where two segments would intersect if extended far enough. For example, the Intersection construction method can be used to create a parking lot adjoining an L-shaped building. The outer corner of the lot should be located at the point where the two outermost walls of the building would intersect if they were extended.
Midpoint
Midpoint 
allows you to place a point or vertex by clicking two points; the new point or vertex is placed at the midpoint of the line between these points. If you were creating street centerlines from parcel data, you might use Midpoint to create the vertices directly between the parcels on opposing sides of the road.
Right Angle
Right Angle 
limits a segment to be at a 90-degree, right angle to the previous segment. You might use the Right Angle construction method to create building footprints or other features that have square corners.
Tangent
Tangent 
adds a segment that is tangential to the previously sketched segment. This method is practical when sketching rail lines in which the curves are nearly always tangential to the previous segment. To create a tangent curve, you need to have already sketched a segment using one of the other sketch construction methods.
Trace
Trace 
helps you create segments that follow along existing segments. Suppose you want to add a new road casing feature that is offset 15 meters from the front of a parcel subdivision. You could trace along the existing line features instead of typing the angle and length of each segment.
