Grip Editing an Alignment in Civil 3D 2021

In this exercise, you will use grips to move alignment curves.

You will learn how to grip edit offset and curb return alignments in the Working with Offset and Curb Return Alignments tutorial.

Note: To change the behavior of an entity, you can change the Tangency Constraint and Parameter Constraint value.
This exercise continues from Editing the Layout Parameter Values of an Alignment.

Note:
Ensure that Dynamic Input (DYN) is turned on, and OSNAP is turned off. For more information, see the Using Basic Functionality tutorial.

Grip edit a free curve entity

Note:
This exercise uses Align-4.dwg with the modifications you made in the previous exercise.

1. Zoom to the area around circle B.
2. Click the alignment. Grips appear at the curve ends, midpoint, and at the point of intersection (PI).
3. Click the midpoint grip at the midpoint of the curve. It turns red.
4. Click a new location for the curve to pass through.
   Notice that the curves and tangents remain tangent to each other, but both endpoints move along the tangents.
5. Click the radius grip directly above the pass-through point grip and experiment with moving it.
   Notice that this grip affects only the curve radius and constrained to the direction of the radius change.
6. Select either an endpoint grip or the PI grip, and experiment with reshaping the curve in different ways.

Grip edit a floating curve entity

1. Pan to the area around circles D and E.
2. Select the grip in circle D. It turns red.
3. Click a new location for the grip.
   Notice that the pass-through point grip in circle F does not move.
4. Select the pass-through point grip in circle E. It turns red.
5. Click a new location for the grip.Notice that the pass-through point grip in circle D does not move. The spiral-curve entity in circle D moves along the preceding tangent to accommodate the new pass-through point.To see how grip editing affects curve specifications, in the next few steps you will add a segment label to the curve. This label shows curve length and radius. The values update each time you reshape the curve.Notice that with this type of curve, if you edit the triangular PI grip, the curve radius does not change.
6. Click Alignment tab >> Labels & Tables panel >> Add Labels drop-down >> Single Segment.
7. Click the curve in circle D. A label is placed on the curve.
8. Press Enter to end the label command.
9. Click the curve to activate the grips.
10. Edit the curve using the pass-through point grip.Notice that while the grip is active, you can use dynamic input to enter a specific pass-through point. You may also enter a specific value in the Alignment Layout Parameters window.
11. Press Esc to deselect the alignment. The label shows the new length of the curve.
12. Close this drawing.

Except where otherwise noted, this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Please see the Autodesk Creative Commons FAQ for more information.