Basics of AccuSnap - MicroStation Tutorial

- In this session, we are going to take a look at the basics of using AccuSnap. AccuSnap is the simplest method to snap to elements based on their geographic points. By default, AccuSnap is enabled, which provides a dynamic method for snapping to elements. A yellow X displays when a viable snap point has been located. Without the yellow X, you do not have a viable snap point. There are several access points for changing and defining the active snap mode. The first access point is to open the snap toolbox. Using the status bar at the bottom of the application windows, locate the snap icon. It looks like an arc with three points. If I left-click on this icon, I can use the button bar to open the snap toolbox. This toolbox provides all the different types of snaps available in MicroStation, but, remember, as I stated in an earlier session, not all buttons are necessarily visible in a toolbox. I need to right-click and select Show All to display all the snap modes available using this toolbox. I will dock this is at the top of my application window so we can review the different snap modes as we use them. Another method for accessing the snap modes is to select the icon again using the status bar and use the pop-up list. The black solid circle indicates that Keypoint is the current snap mode. I can select any snap mode from this list to change the active snap. I will select Intersection. If I click on the snap icon again, you will notice that there is now an empty solid circle on Keypoint and a solid circle on Intersection. The black solid circle represents the current snap mode, and the empty circle represents the running snap mode that is waiting in the background until I use Intersection for one snap, so Intersection is a single shot snap mode and Keypoint is the running snap. Single shot means you get one shot at it, and it reverts back to the running snap mode. The running snap mode will take over again, making Keypoint active. To permanently change the snap mode to Intersection as the running snap mode, hold down the shift key on the keyboard in combination with selecting the Intersection from the list. Now Intersection has a black solid circle, and no other snap has a circle, indicating that now Intersection is the running snap mode. The third access point is using a pop-up menu to see a list of the available snaps. With my cursor in the middle of the View window and using the shift key in combination with issuing a tentative button on the mouse, that's when you hold down both the left mouse and the right mouse buttons simultaneously. It displays a snap menu similar to the one we just used on the status bar, and the rules for controlling running and single shot snap modes are identical. You can also control the running and single shot snap modes using the snap toolbox that we docked earlier. Picking a button will set that snap mode as a single shot snap, while double-clicking on a button will set that snap mode as the running snap. The running snap button will have a dotted hatch on the button to indicate which snap is running. The default snap mode is called the Keypoint snap. The Keypoint snap uses a divisor setting that controls how many snappable points are available on an element. The keypoint divisor is set to two by default. This means that all elements or segments of an element are divided by two to determine which points are snappable. For example, look at the line element. You can see the snappable points as endpoint, midpoint, and endpoint. I have placed graphic representations to demonstrate where the snappable points are on all these element types. The arc is exactly the same as the line. It has an endpoint, a midpoint, and an endpoint. The SmartLine contains the same three snappable points but on each segment of the SmartLine. The same applies to shapes. When you look at the circle, the snappable points are the center point and the four quadrant points. The segments defined by these points are then divided by two, the keypoint divisor, providing quadrant midpoints. Let me demonstrate how you can use these snappable points. First, let me turn off the Snap Points level. Using the Line command, I will snap to the first endpoint of this line. When I hover on the endpoint of the line, you see the yellow X that represents that's a snappable point. The element also highlights, indicating which element's endpoint it belongs to. Now I will issue a left click to start the line at this point. If I move over to the endpoint of the SmartLine, the same yellow X appears to confirm the snappable point. I will issue a left click to input the second point of my line. This guarantees that you have precise points when drawing elements in the design file. It is critical that element points have exact starting and ending points to ensure accurate measurements and designs. Let's look at the circle's snap points. I will left-click to start my new line in the center of the circle and draw lines to each quadrant keypoint snap. Now let's take a look at the snap points available when the keypoint divisor is set to one. Using the view groups list, select the Keypoint Divisor 1 model. Here you can see the difference between the available snap points on each element type from the previous. When the keypoint divisor is set to one, the snappable point is only at the endpoints. The midpoint snap is no longer available. Using view groups, select the Center Snap model. Using the center snap, you can see the snappable points for each individual element type. You no longer have quadrants on the circle or vertex snap points on the other elements. You can only snap to the center of the circle or shapes. The line does have a center snap, but it is exactly the same as the previous midpoint location. The SmartLine has a center snap that is located at is geometric center. I will change my running snap mode to Center using the shift key in combination with the tentative chord on my mouse. Now, using the Line command, I need to hover on the edge of the element to locate the center snap for that element. Using View Group, select the Intersection Snap model. Here you can see that the Intersection snap finds existing and non-existing intersections. First, let's turn off my visible snap locations to make this easier to view. I placed the snap dots on a level called Snap Points. Using the level display dialog, I will turn off that level. Now, using the Line command, I can snap to the existing intersections. To snap to non-existing intersections, I must use the tentative chord on the mouse to identify the first element that I want to use to calculate the intersection with. If I hover over a second element, the non-existing intersection will display as that little yellow X, and I can issue a left mouse button to accept. Let's try that again. I will tentative on the first element and hover on the second element to calculate the non-existing intersection location. Issue a left mouse button or a data point to accept this snap point. Using the View Group, select the Tangent Snap model. There are two types of tangent snaps available. The first tangent I like to call tangent to or from an element. The second tangent point I like to call tangent to or from a point since it will have a fixed tangency point. I will change my running snap mode to Tangent using the shift key in combination with the tentative chord on my mouse. This snap mode will not be available for all geometry commands when it's not geometrically feasible. Using the Line command, hover on the circle to preview the tangent options. As you can see, you can identify the circle, and it will calculate a tangent line from anywhere on that circle or an arc. I can easily draw a tangent line from the circle to the arc. Now, using the circle command, let's draw a circle tangent to the other circle. Using the tool settings dialog, I want to control the tangent circle radius or diameter. I will define the radius as 150 feet and place another tangent circle between the two circles. Now I will change my running snap mode to Tangent Point using the shift key in combination with the tentative chord on my mouse. Using the Line command, I will issue a left mouse button in space and hover on an element to calculate the tangent point. If you hover on an existing element, you will have only one or two tangency points to accept, and once selected, this will be a fixed tangency point. Using View Group, select the Perpendicular Snap model. There are two types of perpendicular snaps as well, the first, Perp, I like to call perpendicular to or from an element, and the second is Perp Point, I like to call perpendicular to or from a point since it will also have a fixed perpendicular point. I will change my running snap mode to Perp using the shift key in combination with the tentative chord on the mouse. This snap mode will not be available for all geometry commands since it's not geometrically feasible for every command. Using the Line command, hover on the circle to get a preview of the perpendicular options. As you can see, you can identify the circle, and it will calculate a perpendicular line from anywhere on the circle or SmartLine. I can easily draw a perpendicular line from the circle to the SmartLine. I will change my running snap mode now to perpendicular point. Using the Line command, I will issue a left mouse button in space and hover on an element to calculate a perpendicular point. If you hover on an existing element, you will only have one or two perpendicular points to accept, and once selected, this is a fixed perpendicular point.