Place Arc

Used to place a circular arc. Arcs can be placed clockwise or counterclockwise. Where an arc is constrained by a snap, such as Tangent or Perpendicular, and more than one result is possible, MicroStation displays icons representing each possible result. In these cases you can use the pointer to select the required solution.

Alternatively, you can use the keyboard and press the:

<Alt> key to switch to the next solution, or key in CONSGEOM NEXTSOLUTION.
<Ctrl> key to select the nearest (to the pointer) solution, or key in CONSGEOM NEAREST SOLUTION.

You can access this tool from the following:

Ribbon: Drawing > Home > Placement > Arc Tools split button
Ribbon: Modeling > Home > Placement > Arc Tools split button
Toolbox: Arcs

Setting	Description
Method	Option menu that sets the method to be used for constructing the arc: Start, Center — Arc is constructed by placing its start point, center point, then sweep angle and direction. Center, Start — Arc is constructed by placing its center point, start point, then sweep angle and direction. Start, Mid, End — Arc is constructed by placing three points defining its start point, a second point on the arc, and its end point. Start, End, Mid — Arc is constructed by placing three points defining its start point, end point, and a third point on the arc.
Radius	If on, sets the radius. `CONSGEOM` `CONSTRAIN` `RADIUS` < `LOCK` \| `SET <value>` \| `UNLOCK` > The button lets you assign a new or existing variable to the value. You will see any existing variables in the drop-down along with options to create a new variable and a new expression. button indicates that a variable is already assigned to the value. ( is available for Radius, Length, Start Angle, Sweep Angle fields)
Length	If on, sets the length of the arc. `CONSGEOM` `CONSTRAIN` `ARCLENGTH` < `LOCK` \| `SET <value>` \| `UNLOCK` >
Start Angle	If on, sets the angle between the view's x-axis and an imaginary line between the start of the arc, and its center. `CONSGEOM` `CONSTRAIN` `STARTANGLE` < `LOCK` \| `SET <value>` \| `UNLOCK` >
Sweep Angle	If on, sets the arc's sweep angle. `CONSGEOM` `CONSTRAIN` `SWEEPANGLE` < `LOCK` \| `SET <value>` \| `UNLOCK` >
Direction	If off, you can define the direction of the arc interactively with the pointer. If on, the direction of the arc is controlled by the option menu. CW — The arc is constrained to a clockwise direction. CCW — The arc is constrained to a counter-clockwise direction. `CONSGEOM` `CONSTRAIN` `CCW` < `LOCK` \| `SET <value>` \| `UNLOCK` >
Solution	If on, and there is more than one possibility for the next data point, lets you choose a solution from the drop-down menu.
Additional key-in settings	Several additional key-ins can be used to control how the tool works: CONSGEOM SET SHOWALTSOLUTIONS <OFF \| ON> — If set to ON (the default), and a constraint snap is used, the tool displays all possible sizes and orientations of the element that would satisfy the snap. The proposed element nearest the pointer location is shown in normal symbology, while other possibilities are shown as dashed in muted color. CONSGEOM SET CONTINUEARCS [OFF \| ON] — If set to ON, when you finish placing an arc by edge, the tool restarts by automatically adopting the last point placed as the start point on the next arc. AccuDraw will be oriented to be tangent to the previous arc. The default value for this setting is OFF. CONSGEOM SET DYNAMICREVERSE [OFF \| ON] — (Direction disabled only) If set to ON (the default), the sweep direction reverses automatically whenever the pointer crosses over the line from the center to the start point. CONSGEOM SET SHOWFEASIBLEREGION [OFF \| ON] — If set to ON (the default), a dashed red line or circle shows where the pointer can move. If it moves outside of this area, a heavy line weight red X displays, indicating that the arc cannot be completed at this location. CONSGEOM CONSTRAIN ARCCHORDHEIGHT [LOCK \| SET <value>\|UNLOCK] — Specifies the distance from the start-end point chord to the peak of the arc. This can be used as an alternative means of defining the arc when the start and end points of the arc are known. It can also be used to define the sweep, given radius, or vice versa. CONSGEOM CONSTRAIN ARCSECTORAREA [LOCK \| SET <value>\|UNLOCK] — Specifies the area of the sector of the circle that is defined by the arc. That is sweep/360pir². This can be used to define the sweep, given the radius, or vice versa. The value must be specified in square master units only.

Key-in: PLACE ARC ICON

Key-in: PLACE ARC < CENTER | EDGE > CONSTRAINED