Perpendicular Line Tool - 3rdTech DeltaSphere-3000 User Manual

appear in which you can enter a specific distance. Positive numbers will move the plane toward
the origin of the scene (where the scanner was located); negative numbers will move the plane
away from the origin. This function is useful for creating regularly spaced contours of a scene
by intersecting the plane with the data set. (See section 8.1.13)

8.1.7 Perpendicular Line Tool

In addition to measuring the distance between two particular points, SceneVision can determine
the distance between a point and a wall, floor or any other flat surface by drawing a
perpendicular line to that surface.
First, create a plane as described in the previous section. Measuring perpendicular distances is
then a simple two-step process – choosing the plane and choosing the point.
Select Draw Perpendicular Line from the Draw & Measure menu, or the corresponding button
( ) from the toolbar. Next, select the plane to which you want to drop a perpendicular. You can
either select the plane from the scene tree, or you can hold Ctrl and select any point in the plane.
(If you just created the plane it might already be selected.) While you hold Ctrl, a perpendicular
line will be drawn from your cursor to the plane – along with its measurement. Click on a point
to complete the perpendicular line. You must click on a valid data point, not a background
point.
As with other annotations, you can pop up the Annotation Properties window. You can also
select and move either endpoint of the line and the entire perpendicular line will move with it.
The label will appear in the Perpendicular lines folder of the scene tree.
Specifying the Length of Perpendicular Lines
It can be useful to create a line perpendicular to a plane of a particular length. For example, you
might want to show the position of a person in a scene and represent his location with a vertical
line. To create such a line, select a plane and the Draw Perpendicular Line function as described
above. Then, hold Ctrl and select a point on the plane. This would seem to create a zero length
line. Instead, it will open a dialog box in which you enter the length of the line.
Once you have created this line there are two ways you can edit it. If you would like to move
the line to a different location on the plane, select the arrow cursor, hold down Ctrl, and drag the
point where the line intersects the plane. It will remain perpendicular and will stay in the plane.
If you would like to change the length of the line, select the arrow cursor, hold Ctrl-Alt, and
drag the other endpoint of the line. The line will remain perpendicular but will change length.
DeltaSphere-3000 3D Scene Digitizer
Note: Even though a created plane displays as a rectangle, it actually extends to
the limits of the data. Perpendicular measurements can be made with points
beyond the visible boundary of the plane.
Note: You must pick a point on the plane annotation – not on the data. You may
need to increase the size of the plane in order to pick a point. If the data is in the
way, turn it off by hitting 'd'.
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