User Guide
User Guide
User Guide
User Guide
User Guide
User Guide
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During a drawing session, much of your time will revolve around joining new elements to existing elements in the design, or modifying existing elements. In manual drafting, this is done by eye. With MicroStation, you can work precisely, letting the system find the exact location of elements, or various points on elements. You can define points relative to other points as well. All this is done using tentative snap points.
A tentative snap point is a form of graphic input that is used to:
Preview the location of the next data point. Accepting the tentative point location enters the data point there.
Define a point of reference for entry of the next data point.
It is also possible to snap a tentative point to an existing element (put it directly on the element). Tentative point snapping helps you accurately construct new elements that are either connected to existing ones or precisely related to existing ones.
Using tentative snaps, for example, you can:
Place a line from the exact end point of an existing element to the midpoint of another.
Place a line perpendicular or parallel to another line.
Place a circle tangent to an arc or a B-spline curve.
Place a cell at the centroid of a shape.
 | Snapping to a point on an element at which that element is overlapped by another element(s) can be difficult, especially when working with complex models. It is sometimes easiest to first bring the overlapped element to “the front”of the view display. An element is said to be in the front if it is not overlapped by any other elements. To bring an overlapped element to the front, select the element and then choose Edit > Bring to Front. |
Snapping is affected by the Snap Lock settings. There are three basic Snap Lock settings: the snap on/off toggle, the Snap Mode, and the Snap Mode override.
If the Snap Lock toggle is off, tentative points do not snap to elements.
When Snap Lock is on, how a tentative point snaps to an element is set by the active Snap Mode (or the override setting if one is active).
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You can set the default Snap Mode via the Locks dialog box, the Snap Mode button bar, the pointer's pop-up menu, or the status bar menu. The Snap Mode (or Snap Mode override) is indicated in the status bar.
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 | The Snap Modes button bar is dockable and resizable. |
There are three snap modes called multi-snaps. Unlike an ordinary snap mode, a multi-snap represents a list of other snaps. When a multi-snap is active, AccuSnap and Tentative Point snap will process the list of snaps that it represents.
By default, multi-snap 1 contains the following snaps: keypoint, bisector, midpoint, origin, intersection. Multi-snap 2 and multi-snap 3 are undefined by default.
You can modify the contents of a multi-snap using the multi-snaps dialog box. The dialog box displays all possible snaps for the multi-snap chosen in the icon bar. Snaps currently included in the chosen multi-snap are marked with a check mark. Snap modes can be included or excluded from the multi-snap by checking or unchecking the corresponding checkbox. The definition of each multi-snap is stored in the user's preference file.
| If the Multi-snaps dialog box is open and a different multi-snap mode is activated, the dialog box automatically displays the contents of that multi-snap. |
During a session, most likely you will use a particular Snap Mode for a majority of operations, but occasionally you want to use a different snap mode. At any time, you can override the active Snap Mode for a single snap by choosing a Snap Mode override. The override mode is effective only for the next operation. After you have snapped a tentative point and accepted with a data point (or Reset), the override is cancelled and the active Snap Mode becomes effective again.
You can set the Snap Mode override via the Settings menu's Snaps submenu, the Snap Mode button bar, the pointer's pop-up menu, or the status bar menu. The active Snap Mode, or Snap Mode override, is indicated in the status bar.
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Snap Mode button bar showing the active snap mode highlighted in speckled gray, and the override snap mode to the right highlighted in light gray | |
With Snap Lock on, each snap mode setting has an effect on tentative snap points. When you enter a tentative point on or near an element, the following occurs:
Snap Mode:
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Tentative point snaps to: |
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Nearest |
 Point on the element nearest to the pointer. |
Keypoint |
 The nearest of the Element keypoints on the element. This is the most generally useful of the snap modes. |
Midpoint |
 Midpoint of the segment of the element closest to the pointer. |
Center |
 Center of elements (such as circles, arcs, text, and so on) with centers. Centroid of other elements, including shapes , line strings, and B-splines. |
Origin |
 Origin of a cell or text, centroid of a B-spline, the first data point in a dimension element, or the first vertex of a line, multi-line, line string, or shape. |
Bisector |
 Midpoint of an entire line string, multi-line, or complex chain, rather than to the midpoint of the closest segment. It also snaps to the midpoint of a line or arc. |
Intersection |
 Intersection of two elements. (Two tentative points are required, although more can be used.) The first tentative point snaps to one element, and that element is highlighted. The second tentative point snaps to another element, and the two segments used to find the intersection of the two elements are displayed in dashed lines. (If the two elements do not actually intersect, but projections of the elements would intersect, the segments include projections of the elements to the intersection.) You can continue snapping until the desired intersection is found; the last two tentative points define where the intersection snap lies. |
Tangent |
 An existing element — the edge of the element being placed is constrained to be tangent to an existing element. The tentative point dynamically slides along the element to maintain the tangency as you move the pointer to finish placing the element. |
Tangent From |
 An existing element — the edge of the element you are placing is constrained to be tangent to the existing element at the tentative point. The tentative point does not move dynamically as you move the pointer, but is locked in place. |
Perpendicular |
 An existing element — the line you are placing is constrained to be perpendicular to the element — the tentative point slides dynamically along the element in order to maintain the perpendicularity as you move the pointer to finish placing the element. |
Perpendicular From |
 An existing element — the line you are placing is constrained to be perpendicular to the element at the tentative point. The tentative point does not move dynamically as you move the pointer, but is locked in place. |
Parallel |
 An existing element, but does not define a point through which the line you are placing will pass. Instead, when you accept the tentative point, the line you then place is parallel to the line to which the tentative point was snapped. |
Through Point |
 Defines a point through which the element you are placing (or an extrapolation of it) must pass. |
Point On |
 To nearest element, as follows: When entering second or later data point, constrains the next data point to lie on it (if it is a closed element) or anywhere on the line on which it lies (if it is a linear element). When entering first data point, constrains the element being placed to extend to that element (or the line on which it lies) from the second data point. |
Multi–snap1 |
 Multi-snap mode 1 by default is Intersection, Keypoint, Nearest. |
Multi–snap2 |
 Multi-snap mode 2 by default is Intersection, Keypoint, Center. |
Multi–snap3 |
 Multi-snap mode 3 by default is Midpoint, Intersection, Center. |
How close the pointer must be to an element in order to snap a tentative point to it depends upon the Locate Tolerance. Locate Tolerance is a user preference that is adjustable in the Input category of the Preferences dialog box (Workspace menu > Preferences). Tolerance values are set in screen resolution (pixels).
A cell is a small drawing — usually of a frequently-used or complex symbol, notation, or detail — created in MicroStation. To snap to the origin of a cell, set the Snap Mode to Origin. When the Snap Mode is not set to origin, tentative points snap to component elements within the cell. For example, when the Snap Mode is Keypoint, tentative points will snap to a keypoint on the line, not the origin of the cell.
Keypoints are regularly-spaced points in an element to which a tentative point will snap when the Snap Mode (or override) is set to Keypoint. The number of keypoints on each segment of a linear element (line, line string, or shape) is one greater than the Snap Lock Divisor setting. If Snap Lock Divisor is 2 (as in all seed files supplied with MicroStation), keypoints are as shown in the figure below. The midpoint of a linear element is a keypoint only if the Snap Lock Divisor is an even number.
| For text, the keypoint is determined by the justification attribute. That attribute and others specific to text elements are described in Text Labels. |
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Element keypoints (with Snap Lock Divisor set to 2 and the text element left top justified). Clockwise from the upper left: Arc, arc, line, line string, text, ellipse, and shape. | |
For example, to create element keypoints on the endpoints and the first, second, and third quarter points of element segments, set Snap Lock Divisor to 4.
AccuSnap provides tentative snap functionality, which may be used stand-alone or in combination with AccuDraw. It provides graphical assistance — a “smart” pointer — for snapping to elements. This automates the tentative snap process, virtually eliminating the need to press the tentative snap button, thus reducing the number of “button presses” required during a design session. When in AccuSnap mode, you simply select a tool and move the pointer over the elements, letting AccuSnap find and display the nearest tentative snap point for you. When the correct snap point is displayed, you enter a data point to accept. If required you can adjusting various AccuSnap settings to configure AccuSnap for your mode of operation.
AccuSnap complements the standard, or manual, method of placing tentative points. That is, even with AccuSnap enabled, you can still use the standard tentative snap method (pressing the tentative button). Additionally, when you are using AccuSnap in conjunction with AccuDraw, you can use AccuDraw shortcuts, which include <U> to suspend AccuSnap for the current tool operation, and <J> to toggle AccuSnap on and off. Alternatively, you can press (and hold down) <Ctrl + Shift> to temporarily toggle AccuSnap on or off, as required.
AccuSnap can be toggled On or Off:
In the AccuSnap Settings dialog box (Enable AccuSnap setting).
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In the Snap Mode button bar (clicking the Toggle AccuSnap button).
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With AccuDraw active and the focus in the AccuDraw window, using the shortcut <J>.
By pressing (and holding down) the <Ctrl + Shift keys>, which temporarily toggles AccuSnap on or off. Releasing the <Ctrl + Shift> keys returns AccuSnap to its previous setting.
AccuSnap works in conjunction with the current Snap Mode setting and, for the most part, is similar in operation to the manual method of tentative snap points — minus the button presses. How close to an element or a keypoint that the pointer must be, before AccuSnap finds it, is governed by the Locate Tolerance setting in the Input category of the Preferences dialog box. These settings can be further refined by the following settings in the AccuSnap Settings dialog box's Feel tab:
Snap Tolerance — for locating elements.
Keypoint Sensitivity — for locating snap points.
Location of snap points on elements still is controlled by the Snap Mode setting.
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With both Show Tentative Hint, and Display Icon turned on — Left: With the pointer within the snap tolerance of an element, AccuSnap shows a prospective snap point with a crosshair (+), along with the current snap mode icon. Right: When the pointer is within Keypoint Sensitivity range, AccuSnap highlights the element and displays the tentative snap point as a heavy line weight “X”. A data point at this stage will be placed at the tentative snap point location. | |
Settings in the AccuSnap Settings dialog box are divided into three tabbed sections — General, Elements, and Feel.
Settings in this group let you enable/disable AccuSnap and you can define AccuSnap's general working mode. By default, Show Tentative Hint and Display Icon are enabled. Both settings give visual feedback on the snapping point and the current snap mode, respectively. Show Tentative Hint is very useful as it shows you visually where the nearest snap point is, even though the pointer may not be in the near vicinity of the snap point.
Show Tentative Hint — With Show Tentative Hint turned on (the default), and snap mode set to Keypoint or MidPoint snap — as you move the pointer over the elements, AccuSnap finds the nearest snap point and displays its location with a crosshair (if the pointer is not within the keypoint snap tolerance), or a heavy line weight “X”, denoting a tentative snap point (if the pointer is within the keypoint snap tolerance). A data point at this stage will be placed at the displayed tentative snap point.
Display Icon — if on, the current snap mode icon displays at the snap point, for both the tentative hint and for the tentative point.
Hilite active element — if on, the element highlights as soon as AccuSnap locates it and the tentative hint displays. If off, the active element highlights only when the tentative snap point is displayed.
For information on all general settings, refer to AccuSnap General Settings.
Controls in this group let you control whether or not AccuSnap snaps to Curves, Dimensions, and/or Text. When snapping is turned off for any of these, AccuSnap will not snap to the particular element, but it will display an icon to show that the element is being ignored.
| Even if snapping to an element is turned off in AccuSnap's settings, you can still snap to the element manually with a tentative snap point. |
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With Curves turned off, AccuSnap displays an icon to show that the B-spline curve is being ignored. | |
Using the controls in the Feel group of the AccuSnap settings you can set AccuSnap's sensitivity when snapping to elements, as follows:
Keypoint sensitivity — lets you adjust how close the screen pointer must be, to the snap point, before AccuSnap snaps to it.
Stickiness — lets you adjust the sensitivity of AccuSnap to the current element. When you have snapped to an element, as long as you move the pointer along that element, the snap system will have a preference for that element over other elements that may have snap points closer to the pointer. The further to the right (+) that you set the Stickiness slider, the further away from the element the pointer may be before AccuSnap will snap to another element.
Snap Tolerance — lets you adjust how close the pointer must be to an element in order to snap a tentative point to it.
AccuSnap enhances many of the standard snap mode settings by displaying and automatically snapping to the next tentative snap point as you move the pointer over an element. With AccuSnap enabled, you very rarely need to enter a tentative snap point manually. In the following examples, it is assumed that a tool has been selected and that Show Tentative Hint and Display Icon are enabled (the default settings).
When working with this snap mode, manually, you move the pointer to the position that you want the snap to be located and then enter a tentative snap point, followed by a data point to accept the location. If the location is incorrect, you move the pointer along the element and enter another tentative snap point.
With AccuSnap, as you move the pointer to the required element, it highlights and the proposed tentative snap point marker displays. To position the “nearest” snap point, you simply move the pointer along the highlighted element, until the required location is reached, and enter a data point.
When you move the pointer over an element in the design, AccuSnap displays the nearest keypoint snap with the crosshair hint, or the tentative point marker if the pointer is within the Keypoint Sensitivity range. To select a different keypoint, simply move the pointer to the required region of the element and AccuSnap will again show you where the nearest keypoint is located.
When you move the pointer over an element, AccuSnap displays the MidPoint Snap location with the crosshair hint, or the tentative snap point marker if the pointer is within the Keypoint Sensitivity range of the midpoint.
When Center Snap is active, the pointer does not have to be close to the actual center point of the element, whether it be a line string, curve, arc, or circle. As soon as you place the pointer over an element, AccuSnap highlights the element and displays the tentative snap point marker at its center point.
When you create an element, the first point defined is its origin. With Snap Mode set to Origin Snap, as you move the pointer over an element, AccuSnap displays its origin point location with the crosshair hint, or the tentative snap point marker if the pointer is within the Keypoint Sensitivity range.
As you move the pointer over an element, AccuSnap displays its bisector point location with the crosshair hint, or the tentative snap point marker if the pointer is within the Keypoint Sensitivity range.
To select the intersection point of two elements requires you to identify both elements. AccuSnap lets you do this by simply hovering over the intersection point of the two elements, without entering tentative snap points. When the pointer is over the intersection point, the elements highlight, one solid and one dashed, and the tentative point marker displays at the intersection point. Where a number of elements intersect at a common point, you can move the pointer until the correct pair of elements highlight.
In a 3D DGN file, the two intersecting lines may be separated in the view Z direction. By default the element nearest the Active Depth of the view is highlighted as a solid line and it is on this element that the data point will be placed. That is, the new element is attached to the element highlighted as a solid line. You can control this by manually snapping to the required element first, before moving the pointer to the intersection point. That is, snap to the element to which you want the new element attached, then move the pointer to the intersection point. The first element will highlight as a solid line, and the remaining element as dashed.
| Tentative Point and AccuSnap can be used together to define an intersection. If a multi-snap is active and contains intersection snap when tentative is snapped, then tentative + AccuSnap selects the intersection. Tentative selects one of the snaps contained in the multi-snap. If the cursor moves over another element with AccuSnap enabled, AccuSnap selects the closest intersection with the first element, ignoring the snap mode chosen by Tentative and ignoring the other contained snap modes. |
(For AccuSnap, applies only when using the Place SmartLine tool) The Fixed Point for Perp./Tan. From setting in the General tab of the AccuSnap settings determines whether Tangent Snap, or Tangent Point Snap is used when either snap is active.
When you are placing a SmartLine with either Tangent Snap, or Tangent Point Snap, as the active snap mode, setting Fixed Point for Perp./Tan. From to:
On — sets the snap mode to Tangent Point Snap.
Off — sets the snap mode to Tangent Snap.
(For AccuSnap, applies only when using the Place SmartLine tool) The Fixed Point for Perp./Tan. From setting in the General tab of the AccuSnap settings determines whether Perpendicular Snap, or Perpendicular Snap Point is used when either snap is active.
When you are placing a SmartLine with Perpendicular Snap, or Perpendicular Snap Point, as the active snap mode, setting Fixed Point for Perp./Tan. From to:
On — sets the snap mode to Perpendicular Snap Point.
Off — sets the snap mode to Perpendicular Snap.
When a multi-snap mode is active (by default or override), AccuSnap processes the snaps in the order they are listed. AccuSnap selects the first snap mode in the list that is hot and on the target element. If none of the snap modes are hot or on the target element, AccuSnap chooses the nearest to the cursor.
| Center is an example of a snap that can be hot but not on the target element. |
| Snaps displayed in the Multi-snaps dialog box are listed in the order in which they are processes by AccuSnap. The order of the snaps can be changed by clicking on a snap mode and dragging it up or down in the list. |
Tentative points let you see where the next data point will be placed before you are committed. They also let you define a data point relative to the tentative point. You can specify the distance from the tentative point using a key-in or, better still, using AccuDraw and its input window. The exact location of tentative points, on elements, are determined by the current Snap Mode, or snap override, setting.
You can enter tentative snap points manually, or you can turn on AccuSnap and let it display tentative points interactively as you move the pointer over elements in a view. With AccuSnap active, when the Tentative Point marker displays, you can enter a data point to accept it. Even when AccuSnap is active, you can enter a tentative snap point manually, by pressing the Tentative button on your system's graphical input device. For information about determining the location of the Tentative button and other MicroStation buttons, see “MicroStation and Graphical Input”.
When using AccuSnap, to snap to elements, only one button press is required. You let AccuSnap find and display the tentative snap point.
When Tentative Point snap encounters a multi-snap mode, it evaluates each snap mode in order, building up a list of candidate snaps for the current target element. Each successive tentative point snap steps to the next candidate snap. When the end of the list of candidate snaps for the current target element is reached, the next target element is picked and a new list of candidate snaps is created, and so on.
| Snaps displayed in the Multi-snaps dialog box are listed in the order in which they are processes by Tentative Point snap. The order of the snaps can be changed by clicking on a snap mode and dragging it up or down in the list. |