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Arc From 3 Points

Sketcher

Description

The Sketcher CreateArc tool creates an arc from its center and its endpoints. introduced in 1.0: Or optionally from its endpoints and a point along the arc.

Arc created in Center mode with automatically applied constraints defined by entering all On-View-Parameters

Usage

See also: Drawing aids.

Pos-OVP = Positional On-View-Parameters. introduced in 1.0
Dim-OVP = Dimensional On-View-Parameters. introduced in 1.0

1. There are several ways to invoke the tool:
   • Press the Arc From Center button.
   • Select the Sketch → Geometries → Arc From Center option from the menu.
   • Right-click in the 3D View and select the Arc From Center option from the context menu.
   • Use the keyboard shortcut: G then A.
2. The cursor changes to a cross with the current tool mode icon.
3. The Arc Parameters section (introduced in 1.0) is added at the top of the Sketcher Dialog.
4. Optionally press the M key or select from the dropdown list in the parameters section to change the tool mode:
   • Center:
     1. Pick the center of the arc. Or with Pos-OVP: enter its X- and/or Y-coordinate.
     2. Pick the start point of the arc, this also defines the radius. Or with Dim-OVP: enter the radius and/or start angle of the arc. The angle is relative to the X-axis of the sketch. No constraint is created for this angle.
     3. Pick the endpoint of the arc. Or with Dim-OVP: enter the aperture angle of the arc.
   • 3 rim points: introduced in 1.0
     1. Pick the start and end points of the arc. Or with Pos-OVP: enter their X- and/or Y-coordinates.
     2. Pick another point to define the radius. Or with Pos-OVP: enter its X- and/or Y-coordinate. No constraints are created for this point.
5. The arc is created and applicable Pos-OVP and Dim-OVP based constraints are added.
6. If the tool runs in continue mode:
   1. Optionally keep creating arcs.
   2. To finish, right-click or press Esc, or start another geometry or constraint creation tool.

Notes

• An arc has 5 degrees of freedom (DoF). Constraining its end points and its center to other existing and static points with coincident constraints would need 3×2=6 DoF. To avoid over-constraining, 2 points of the arc can be coincident to these existing points, but the last constraint needs to consume only one DoF. It can be a horizontal or vertical constraint for example. If both end points have coincident constraints, applying a radius dimension or equal constraint to define the radius of the arc can also work.

Line

Arc From 3 Points

Sketcher