When drawing in TOP view, the user does not know if the curves they are drawing are flat or not. Ensuring curves are flat or "planar" is important in creating surfaces from curves.

Inputing Dimensions

Inputing Location / Dimensions

Planar Snap

• The planar snap ensures that successive curve control points lie flat on the cplane unless snapped to another object.

  Precision

Project to Cplane

• Curves which appear flat from TOP may be space curves in fact if a control point snaps to another object higher in Z height.
• This freeform curves appears flat.

• In fact this curves is actually a space curve, which we can see if we switch to PERSPECTIVE view.

• Switching to TOP view and using the command ProjectCurvetoCplane will force the curve to lie flat.

<aside> 💡 ProjectCurvetoCplane will automatically duplicate your curve. Typically you will want to specify the subcommand Delete Input = True

</aside>

See extensive documentation of Planar Curves here.