Use the Alignment Layout Tools to add complex curve groups to your alignment. Complex curve groups consist of multiple curves and spirals and are available in compound and reverse solutions.
Complex free curve groups are defined by the radius of each curve and the length or A value of each spiral. Additionally, a second parameter must be specified for either of the two curves.
Add a free spiral-curve-spiral-curve-spiral group between two tangents.
When the attachment tangents (1, 2) are edited, the curve radii (3, 4) and spiral lengths (5, 6, 7) do not change. The attachment points and the curve lengths adjust to accommodate edits to the attachment tangents. The length of any of the spirals can be zero.
The compound Spiral-Curve-Spiral-Curve-Spiral (SCSCS) group is placed between two tangents. This group is similar to the spiral-curve-spiral (SCS) group, but it has a second curve and spiral at the end of the group.
The SCSCS group accepts zero as a spiral length, which allows you to create a multiple curve group with or without spirals. Any of the spirals in this group can have a zero length. A spiral with zero length is effectively omitted from the group. The following combinations are possible by specifying zero as the spiral length: SCSCS, SCSC, CSCS, CSC, SCCS, SCC, CCS, CC.
You cannot grip edit the SCSCS group, but you can edit the tangents to which it is attached. The point of intersection (PI) of the original tangents is maintained, which causes the entire curve group to react to changes to either tangent. You can edit the spiral or curve parameters directly in either the Alignment Layout Parameters window or the Alignment Entities vista. If a spiral in the group has zero length specified, the spiral parameters are still displayed.
You can specify an extended tangent length, start point on a tangent, subtended angle, or pass-through point. Enter C to switch the curve for which you will enter the parameter.
Add a free reverse spiral-curve-spiral-spiral-curve-spiral group between two tangents that are nearly parallel.
This group consists of two successive spiral-curve-spiral groups in opposing directions. When the attachment tangents (1, 2) are edited, the curve radii (4, 7) and spiral lengths (3, 5, 6, 8) do not change. The attachment points and the curve lengths adjust to accommodate edits to the attachment tangents.
You cannot grip edit the reverse SCSSCS group, but you can edit the tangents to which it is attached. You can edit the spiral or curve parameters directly in either the Alignment Layout Parameters window or the Alignment Entities vista.
You can specify a start point on a tangent, subtended angle, or pass-through point. Enter C to switch the curve for which you will enter the parameter.