Rays are a special type of construction line with only one end point extending infinitely in one direction.

Angular Ray

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1. Select a point for the end of the ray will pass. Select a second point, or enter the slant in the Inspector Bar.
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2. The ray is created, with the properties assigned to the construction layer.

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Horizontal Line, Vertical Line

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1. Select the point through for the end of the ray.
2. Continue creating ray lines of the same type, and select Finish when done.

Local menu options:

 
Flip: the Flip option changes the direction of the ray 180 degrees.