In the Sketch or Profile environment, select a curve.
Choose Inspect tab→Analyze group→Curvature Comb→Show.
Tip:
If the curvature comb does not display when you click the button, check the Inspect menu to make sure the Curvature Comb command is selected.
You can also click the Clear All Combs option on the Curvature Comb Settings dialog box to clear the display of all curvature combs. To display the Curvature Comb Settings dialog box, on the Inspect menu, click Curvature Comb Settings.
Curvature Comb Settings command