Problem

Snap modes are disabled using SmartLine.
Some snap modes (Tangent, Parallel, Perpendicular) are disabled (grayed out) when using SmartLine.
Snap modes are disabled when AccuDraw is disabled.
Snap modes are disabled when in a 3D file.

Solution

Enable AccuDraw.

Starting in MicroStation V8i, the constraint snaps are not available in a 3D file if AccuDraw is not enabled.
AccuDraw is used to assist these constraint snaps when using SmartLine.
Place line still uses the old behavior.

To be able to use these snap modes with SmartLine, enable AccuDraw (Toggle is located on Primary toolbox).

Notes:
Originally reported as a problem in TR# 226975