EazyDraw vector drawing, tape measure tool. Drawing Tangent and Perpendicular EazyDraw Raw App For Help

The "Measuring Tape Tool" will locate and indicate the slope of a curve. In this mode the tool provides a mechanism to add a line to the drawing that is tangent or perpendicular to the curve.

The "Measuring Tape Tool" needs to be in use for these features to be available.

There is another method for drawing tangents and perpendiculars. This is applied in conjunction with vertex snapping , accessed from the Format main menu - Grids and Guides submenu. Follow the above link to learn more about this method. It is used to draw a line "from" a defined point tangent to a curve. Where this technique described here is used to draw a tangent "to" a defined point on a curve.

Graphics that are NOT selected are not specifically reported by the Tape Measure cursor. Select graphics of interest to enable automatic creation of these precision lines.

The light green "point-angle" cursor read-out needs to be active for these actions to enable. Holding down the Apple-Command key while moving the cursor close to a curve will, in some cases, switch the cursor to this mode. For some shapes the cursor will need to be on one side or the other of the curve for this cursor to be the one displayed.

The "Measuring Tape Tool" has the same behavior as the Arrow Tool with the addition of a live on-screen readout of the exact cursor position, key graphic parameters, or various distances.

The first steps are to select the target curve and enable the Tape Measure tool. Then position the cursor at the point of the curve where the tangent or normal is needed.

When the cursor is close to the target curve, the cursor read-out will change to a light green and report the point on the curve and the angle of the tangent at that point. These may be reviewed before going to the next steps. If you are not able to get the cursor at exactly the precise position, type the letter "i" (for zoom In) to gain more control over the precise position of the point on the curve.

The tape tool allows creation of a tangent or normal to a curve. Type the letter "t" when the cursor is showing a tangent and a line precisely tangent to the curve is added to the drawing.

The tape tool allows creation of a tangent or normal to a curve. Type the letter "n" or "p" when the cursor is showing a tangent and a line precisely perpendicular to the curve is added to the drawing.

To obtain both a tangent and normal line at the exact same point on the curve; stop all mouse movement by taking your hand away from the mouse or touch-pad. After mouse movement is stopped make a visual review of the numerical read-out of tangent and position of the cursor, then type "t" and "n".

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The tangent and normal lines added are centered on the point of the tangent to the curve and they have Pinned angles and centers. If a line that originates precisely at this point is needed, drop both a tangent and normal. Then enable Snap Vertices . Next remove Center Pinning and leave Angles Pinned. Now each line may be adjusted and snapped at other line’s mid-point. This action will allow all possibilities of lines centered or originating at the point of tangency to the curve.

One can trim the tangent and normal lines at their intersection, but this will also cut the curve. For this reason the above technique is more appropriate for generating lines that originate at the tangent point.

You can use the keyboard to zoom in or out, just type "i" to zoom in and "o" to zoom out. The zoom action is centered on the mouse cursor location, if it is over the frontmost drawing window. It is centered on the center of the window if the mouse is off the screen. This means that by repeatedly typing "i" while positioning the cursor you may place the cursor as accurately as needed. This technique is also needed if another point of interest such as a vertex is close to the point where the tangent is needed, in this case the cursor may be reporting the position of interest and not the tangent angle, but by zooming in the interfering point may be avoided.

When zoomed in, the lines added will be shorter in an absolute measurement. The can be edited in the normal manner to obtain the desired length and position. The lines are not locked to the originating curve, they are free to be moved anywhere on the drawing. Use the Lock feature if this needs be avoided.