Exercise 21 – Cursor Snaps
You may have noticed the cursor changes appearance slightly as you move it to different locations in your drawing.
If you hover over an entity a Diamond appears, if you’re near a Point or End of a line or arc or curve a small Square appears, if you’re close to the mid-point of a line or the centre of a circle a small Circular Dot appears and if you’re close to the intersection a Cross appears.
Cursor Snaps & Grid Snaps
Cursor snaps take priority over snapping to the grid. You can accurately snap to geometry in your drawing without having to switch the grid snapping mode off.
In the following exercise we’ll explore these cursor snap modes. You’ll need to have a steady hand and be sure to hold your mouse still as you click to avoid slipping away from the snap zone.
- Open the file named ‘Snap-Happy’ from the training folder and use Zoom Fit to make the image fill your view.
Use the zoom tools to help as you work on the drawing. There is no need to strain your eyes!
- Select Insert Line from the icon menu.
- Move your cursor over the drawing to where it says ‘Start Here’, position P1 in drawing ‘A’.
Notice that your cursor changes as you get near the end of the arc. A small SQUARE should appear.
This indicates you’ve found the end point of the arc.
- Whilst the square (NOT diamond) is visible, click and release the left button to snap to that position. Then check the prompt!
- Move your cursor to the point at position P2 until the square appears on your cursor. Again, click and release the left button to snap to the point.
- Repeat for positions P3 and P4. Right click to finish the current line.
- Move your cursor to P5 and snap the start of your new line. Continue at P6, P7, P8, P9 and finish back at P1. Right click to finish the current line.
- Repeat the above for points P10, P11 then P12 and P13.
Now let’s move on to the next example, ‘B’.
- Move your cursor to where it says ‘Start Here’ at position P1 in drawing ‘B’ and snap to P1.
- Continue snapping for P2 thru to P9, and right click to finish the current line.
- Start the new line at P10. Move across to P11 then up to P12, P13 and P14. Right click to end.
- Now move your cursor directly over the line at about position P15.
This time you’ll notice your cursor shows a DIAMOND and not a square. There are no points to snap to but there is a line you can lock onto.
- When you see the diamond, left click and notice your new line is now attached to the selected line and extends away from it and is perpendicular to it (a right angle, 90 degrees).
- Now move your cursor to P16 and snap to that point. Right click to end the line.
- Repeat the above for P17 and P18 and again for the points P19 thru to P28. You will again notice that the lines you draw are perpendicular to the entity you’re selecting with the diamond cursor.
- Draw the last line by moving your cursor over the vertical line at about P29 (the mast of the boat) until you see the diamond and left click the mouse button. Right click to end.
If you don’t want to snap but the cursor indicates a snap position, hold down Ctrl (Command⌘) to temporarily disable cursor snapping.
Now let’s use the other cursor Snaps for locating the centre/origin and Intersections.
- Zoom in to drawing ‘C’ so it fills your screen and make sure you’re still in line drawing mode.
- Move your cursor to the centre of the circle at about P1 until the cursor changes to a small circular dot and click to snap to the middle of the circle.
- Repeat for the arc near P2, and the middle of the line near P3, P4, P5, P6, and P7.
- Now locate the intersection of two lines at P8 and P9. You should see a cross shaped cursor.
- Try locating more snaps in the drawing and also try holding down Ctrl (Command⌘) when a snap is located to temporarily disable the snap mode and click in free space.
- Use File, Save-as to save your finished drawing as My Snap Training
Exercise 22 – Tangents
Use the File, Open command and locate the Training folder. Open the file named ‘On-a-Tangent’.
- Select the Arc by Three Points
- Click on the circles at positions P1, P2 and P3. An arc will be drawn that is just touching tangent to the three circles you selected
- Repeat for P4, P5 and P6, then for P7, P8 and P9, then for P10, P11 and P12 and then P13, P14 and P15. Finally select P16 then snap to point P17 before finishing the arc at P18.
- Now select Insert line command and with diamond showing, select circles at P19 and P20
Your drawing should look like this
Well done. You’re a genius!