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Plotting arcs and circles |
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Use the following commands to create arcs and circles in KOMPAS-3D:
•Arc by two points with direction,
By default, each of these commands results in a circular arc. To plot a full circle, press the Circle 
button in the Arc group on the Parameter Panel.
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The arc plotting commands are combined in a group. While executing a group command, you can switch to execution of another one using buttons of the Parameter Toolbar header. You can also transfer any parameters you’ve specified between the commands of a group. |
To build an arc passing through three specified points, use the Arc by Three Points 
command.
Step-by-step instructions
Set the starting, end, and intermediate points of the arc using the element groups Starting point (1), End point (2), and Point on the arc (3) on the Parameters Panel. How to set a point:
•Enter the coordinates or define a point object. The procedure is the same as when creating a point in rectangular coordinates.
•Plotting a point. To do this, click the Build Point 
button located on the right side of the Snap Point field. Will start subprocess of plotting a point.
After specifying three points the arc is automatically created. Its icon 
appears in the model Design Tree.
To complete operation of the command, click Finish 
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When you plot an arc using this method, you should specify the center point, starting and ending angle, arc radius and its base plane. Base plane is an already existing plane in a model. The plane of the arc should be parallel to the base plane.
To build an arc by center and radius, use the Arc by center and radius 
command.
Step-by-step instructions
1.Set the central point of the arc 1 using the Center (1) group of controls on the Parameter Panel. How to set a point:
•Enter the coordinates or define a point object. The procedure is the same as when creating a point in rectangular coordinates.
•Plotting a point. To do this, click the Build Point button located to the right of the Snapping Point field. Will start subprocess of plotting a point.
After you specify the start point, the position of the plane of the arc is automatically determined: this plane passes through the center of the arc parallel to the base plane. By default, the base plane is one of the coordinate planes.
2.You can change the base plane if needed. To do this, specify an object in the graphic area or in the Design Tree.
The name of the base plane is displayed in the Base Plane field.
3.Set the following parameters of the arc: starting and ending angle, and diameter (or radius). How to set:
•Enter the value in the corresponding field on the Parameter Toolbar.
To indicate whether the diameter 
or radius 
will be set, press the required button in the Parameter group.
•Enable the Snap Point field and set an arbitrary point in the space or a point object. The value of the angle or radius will be determined by the projection of this point to the plane of the arc. If a point object is selected, its name is displayed in the Snap Point field.
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A point specified to determine the initial angle of an arc, also determines its radius/diameter, and vice versa. If you need to use different point for these parameters, then set one point, activate the field of the parameter and select the point object. |
The arc is created automatically after the center and two points are set. Its icon appears in the model Design Tree.
To complete operation of the command, click the Finish .
Arc by two points with direction
When you plot an arc using this method, you should specify the start and end points of the arc and the tangent direction in one of these points. To set the tangent direction in a certain point, you can use a guiding object or a vector.
To build an arc by two points with direction, use the Arc by two points with direction 
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Step-by-step instructions
1.Set the start and end points of the arc using the Starting point (1) and End point (2) groups of controls on the Parameter Panel. How to set a point:
•Enter the coordinates or define a point object. The procedure is the same as when creating a point in rectangular coordinates.
•Plotting a point. To do this, click the Build Point button on the right side of the Snap Point field. Will start Subprocess of plotting a point.
2.Set the direction of the tangent in the start point or in the end point. To do that, go to the required group of controls (Starting point (1) or End point (2)) and perform one of the two possible actions:
•Set a guiding object: enable the Direction in point field and select the object in the Design Tree or in the graphic area.
The name of the object is displayed in the Direction in point field.
•Vector construction: press the Build vector 
button to the right of the Field Direction at point. Will start the process of vector construction.
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If an arc should be mated with an existing curve, you should specify the point of this curve as the starting/end point: a starting or end point, or a point built using the On CurveeitherAt intersection, and as the guide object at this point – the curve itself. |
After setting two points and the direction, the arc is automatically created. Its icon appears in the Design Tree.
To complete operation of the command, click Complete .
If an arc is plotted using this method, you need to specify a curve, to which the arc circle should be tangent, as well as the center of the arc, the starting and ending angle.
To plot an arc tangent to a curve, use the Arc tangent to a curve 
command.
Step-by-step instructions
1.Select the curve to which the arc circle should be tangent. To do this, select the desired object in the Design Tree or in the graphics area.
The name of the selected object is displayed in the Curve field on the Parameter Panel.
2.Set the central point of the arc using the Center group of controls on the Parameter Panel. How to set a point:
•Enter the coordinates or define a point object. The procedure is the same as when creating a point in rectangular coordinates.
•Plotting a point. To do this, click Plot Point located on the right side of the Snap Point field. Will start subprocess of plotting a point.
After you specify the center of the arc, the position of its plane and its radius are determined. The plane goes through the straight line tangential to the selected curve in the point closest to the center of the arc.
3.Modify the arc radius (or diameter) if needed. To do that, in the Parameter group, click the desired button — Diameter /Radius and enter the value in the corresponding field.
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When a radius/diameter is changed, the center of the arc moves within its plane. Hence, if the center of an arc is linked to a point object, it is not possible to modify the radius/diameter of the arc. |
4.Set the starting and the ending angles of the arc. To do that, perform one of the two possible actions in the Starting point (2) and End point (3) groups:
•Enter the value in the Angle field.
•Enable the Snap Point field and set an arbitrary point in the space or a point object. The value of the angle will be determined by the projection of this point to the plane of the arc. If a point object is selected, its name is displayed in the Snap Point field.
The arc is created automatically after the center and two points are set. Its icon appears in the Design Tree.
To complete operation of the command, click the Finish .
•You can use the geometrical calculator.
•You can assign tolerances to the values of the operation parameters expressed in linear and angular values. To do this, call the Tolerance command located in the menu of the required parameter, or click the 
icon displayed in the parameter field (the icon is displayed if a tolerance is assigned to the parameter value). More details on assigning tolerance...
