Wasn't it frustrating that not all the snap modes were available with the Place SmartLine tool in MicroStation/J? For example, to place a line tangent to a circle or arc, you had to use the Place Line tool. A nice little enhancement in V8 is that SmartLine's capability has been extended to allow the use of Perpendicular and Tangent snaps and their fixed-point counterparts.
When you select the Place SmartLine tool, it now is possible to select the Perpendicular and Tangent snap modes from the button bar. Alternatively, you can select Perpendicular, Perpendicular Point, Tangent or Tangent Point from the snaps pop-up menus. This functionality extends even further when using Place SmartLine with AccuSnap.

The "Fixed Point for Perp./Tan. From" setting in the General tab of the AccuSnap settings dialog box offers the fixed-point option when using the Tangent or Perpendicular Snap mode with AccuSnap.

If we consider this in the context of Tangent snap, when "Fixed Point for Perp./Tan. From" is on, and the snap mode override is set to Tangent, AccuSnap fixes the start point of the line at the closest Tangent point of the circle.

If "Fixed Point for Perp./Tan. From" is off, with the snap mode override set to Tangent, AccuSnap allows you to draw a line tangent to the circle. The second data point determines the tangential line's final position.

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