Chapter Seven Input of Precise Geometric Data INTRODUCTION PLAY VIDEO A very useful feature of MicroStation V8i for precise technical drawing is key-in of coordinate data. Whenever MicroStation V8i calls for entry of coordinate data, the data may be entered: via the mouse and graphic cursor, or via coordinates entered from the keyboard. ENTERING PRECISION COORDINATES USING ACCUDRAW AccuDraw normally opens automatically, however, if is not active, it can be started by clicking on the AccuDraw icon located on the Primary tools tool bar docked at the top of the application window. This will open a coordinate dialog showing X and Y coordinates. As an example of how to operate AccuDraw, open any scratch file or start a new file and do the following: 1. Select the Place Line tool. 2. Start a line by placing a data point in the lower left corner of your view. Move your cursor to the right so the line is horizontal. Note how the line highlights to indicate that it is perfectly horizontal (AccuDraw Y field shows 0.) Vertical works the same. This is called indexing to X or indexing to Y. Copyright 2009 Bentley Systems, Incorporated Input of Precise Geometric Data 1
3. Move the cursor horizontally to the right and then type 5 (don t press Enter). AccuDraw will make the line 5 units in X. Data point to set the line. 4. Move the cursor straight up and type 3. The line is 3 units in Y. Data point to set the line. You now have two lines, one horizontal exactly 5 units long, the other a vertical one 3 units long. 5. Press the space bar to switch between x,y mode and polar coordinate mode in AccuDraw. In the polar coordinate mode you enter distance and angle in the coordinate dialog. 6. Press the space bar again to return to the rectangular coordinate mode. 7. When drawing a line, press Enter to set Smart Lock. Smart Lock will lock your direction in either X or Y depending on the current position of your cursor from the AccuDraw compass at the time you press Enter. If you are further along the X axis than the Y axis, the lock is set to X. If you are further along the Y axis than the X axis then the lock is set to Y. 8. To start a line at a known distance from a point, do this: first select the Place Line tool, then move your cursor so the yellow X appears one of the vertices of the lines. This is AccuSnap snapping to one of the keypoints of the line, in this case an endpoint. 9. Next press the function key <F11> (this forces input focus to AccuDraw). Press the letter O on the keyboard. This sets the AccuDraw compass at the snapped location. Move the cursor so it indexes as explained in step 2. Type the distance from the known point and then left click to set the beginning of the new line. ENTERING ABSOLUTE COORDINATES If you need to enter the absolute coordinates of a point: With input focus on AccuDraw (press <F11>), type the P key. Note the dialog says x,y= with a box to input a number. Here you type the coordinate pair x,y and then <enter>. There is a lot more to AccuDraw, but, that is enough to get started. If you practice these steps you will find that AccuDraw is the easiest way to enter precise coordinates. You will work with AccuDraw more in later exercises. Copyright 2009 Bentley Systems, Incorporated Input of Precise Geometric Data 2
EXERCISE: DRAWING A STEPPED SHAFT In the next three exercises you will use several tools to create and dimension the following stepped shaft design. For accurate coordinate entry, you will use a combination of snaps and AccuDraw. The overall design of the stepped shaft. DRAWING THE SIDE VIEW OF THE DESIGN In this part of the exercise you will draw the side view of the stepped shaft. 1. Select File menu > New. Enter the file name SteppedShaft. 2. Select Settings menu > Design File > Working Units category. Set Master Units to Inches. Set Label to quote mark ( ) to represent inches. Set the format field to MU to use Master Units (1.25 instead of 1:2.5) Set the Accuracy field to 0.123 Copyright 2009 Bentley Systems, Incorporated Input of Precise Geometric Data 3
3. Click OK to close the Design File settings dialog. 4. Make sure AccuDraw is on. If not, click its icon in toolbox docked on the upper part of the MicroStation window. 5. Select the Place Block tool. 6. Make sure the Input Focus is on AccuDraw (click on AccuDraw dialog or press F11 function key). To place first rectangle with corner at 0,0: press the P key and type in 0,0 <enter>. 7. Move the cursor to the right of the first point and type 4 (without pressing <enter>). Move the cursor straight up and type 4 (without pressing <enter>). Enter a data point to place the block. 8. Use Fit View from the View toolbox at the top of the View 1 window to see the 4 inch by 4 inch rectangle (block). Next, you will accurately place the second block using AccuDraw s Origin feature. 9. Use Zoom Out from the View toolbox to zoom out a little so you have room to draw your next element. Press Reset to return to your active tool. 10. Verify the Place Block tool is still active. Move the cursor to the lower right corner of the first rectangle until a yellow x appears. This is AccuSnap snapping to the keypoint (a vertex) on the first block. 11. With the input focus on AccuDraw (<F11>), press the letter O (for Origin) to set the AccuDraw origin. The AccuDraw compass now appears at the lower right corner of the first rectangle. 12. Move the cursor up along the rectangle s right side (Y direction), type 1 and data point. This places the first point of the second rectangle 1 above the right corner of the first rectangle. 13. Move the cursor to the right and type 6 (don t press Enter) for the width of second rectangle. 14. Move the cursor up in the Y direction and type 2 for the height of the second rectangle. Enter a data point to complete the second rectangle. Use Fit View tool to see the first and second rectangles. (see figure to right). Copyright 2009 Bentley Systems, Incorporated Input of Precise Geometric Data 4
15. Select the Chamfer Tool from Modify task bar (7W). 16. In Tool Settings, set both distances to 0.125 (1/8 ). Data point on the right hand vertical edge of the 6 x 2 rectangle. 17. Click on the top horizontal edge of the same rectangle and a final data point to accept the chamfer. Observe how the upper corner is now chamfered to 1/8. 18. Repeat on the lower right corner of the same rectangle (see figure at right). 19. Draw the vertical line at the chamfer using AccuSnap and two data points(see figure to right). Press Reset to complete placing your line. DRAWING THE END VIEW OF THE DESIGN In this part of the exercise you will create the end view of the stepped shaft by placing a center line and circles to represent the diameters of the different features of the shaft. 1. Move cursor to the Line Style menu on the Attribute toolbox docked at the top of screen. Choose the center line style. 2. Place the center line using the Place Line tool. Snap to the center of the vertical edge of the rectangles and data point. 3. Use the Modify Element tool (71) to extend the line to make the center line as long as you like. (Click Modify tool, then click on the end of the center line that you wish to stretch and then move your cursor). Copyright 2009 Bentley Systems, Incorporated Input of Precise Geometric Data 5
4. Pan your view to the right to make room for the end-view circles. You pan by using the pan icon in the View Control task bar (or press and hold the wheel on your mouse and move your hand). 5. Change line style back to solid (0). Next, you will place a circle that represents the outside diameter of the small shaft of the design. 6. Select the Place Circle tool (E1). 7. In the Tool Settings window set the following settings: Method: Center Turn on the Diameter option Enter 2 in the diameter field (sets the circle diameter to 2 ) 8. Snap to the right end of the center line and data point. This places the fixed diameter circle matching the smaller shaft. Next, place another circle that represents the large shaft. 9. In the Tool Settings window, change the diameter value to 4. Snap to the center of the existing circle and data point. All that remains is to place the circle that represents the chamfer. Instead of using the Diameter option in the Tool Settings window you will use AccuDraw to set the size of this final circle. 10. Uncheck (turn off) the Diameter option in the Tool Settings window. 11. Snap to the center of the two circles already placed. 12. Move your cursor to the right of the center point of the new circle keeping it indexed on the X axis of the AccuDraw compass. Type 0.875 which will appear in the X field of the AccuDraw toolbox. 13. Data point to accept the placement of the chamfer circle. Copyright 2009 Bentley Systems, Incorporated Input of Precise Geometric Data 6
DIMENSION THE DESIGN In this part of the exercise you will place several dimensions to document the stepped shaft design. 1. Select Element menu > Text Styles. Set text height and width to 0.200. Close the Text Styles window. 2. Select Dimension Element (F1) from Dimensioning toolbox. Click on the top horizontal line on the large portion of the shaft. A dynamic dimension appears. Drag the dimension up and data point to set its location. 3. For the 10 dimension, select Dimension Linear (F2). 4. Snap to the upper left corner of the shaft (same place where left edge of the previous dimension appears). Data point to accept. 5. Snap to the far right end of the shaft on the chamfered edge. This sets the distance to be dimensioned. 6. Move the cursor up to set the location of the dimension above the first dimension you placed. Data point to accept the location. Your dimension should read 10 for 10 inches. Next, you will place the diameter dimensions on the circles to the right. This involves the use of the Dimension Element tool again. 7. Select Dimension Element tool (F1). Identify the 2 circle. Note how the options in the Tool Settings window change to match the type of element being dimensioned. Copyright 2009 Bentley Systems, Incorporated Input of Precise Geometric Data 7
8. Select the Dimension Diameter icon in the Tool Settings window (middle icon). 9. Identify the 0.875 radius circle you placed earlier with AccuDraw. Position the dimension to the left of the circle and data point. 10. Dimension the 4 circle. 11. If necessary, use the Modify Element tool (71) to modify the dimension locations so they don t interfere with one another. At this point, you have completed your stepped shaft mechanical design using AccuDraw for precision input of the coordinate data. < RETURN TO TABLE OF CONTENTS GO TO CHAPTER EIGHT > Copyright 2009 Bentley Systems, Incorporated Input of Precise Geometric Data 8