Arc 3 Points - Center/ Endpoints


This topic will explain the Arc 3 Points - Center / Endpoints function,will explain where to find the function, and explain the options foundin it.This topic will also give a brief description of Dynamic Drawing,the Snap Increment function, explain creation with quick steps, and providelinks to related topics.

The Arc 3 Points - Center / Endpoints Function

The Arc 3 Points - Center / Endpoints function is used to create arcsof a specified radius, and start and end angles, by defining three pointsin the graphics area.The first assigns the center point, the second definesthe start angle and the radius of the arc, and the third sets the endangle or the arc.Once active, the entity can be modified with data entry.

Dynamic Drawing

This function supports Dynamic Drawing which allows you to use a combination of sketching and data entry to create the entities. After initially sketching the entity, it becomes an active entity, which is an entity that is in Modify Mode. Entities in Modify Mode display in the current Entity color, but displays with a greater line thickness to make them easier to identify. Active entities can be modified using data entry. The benefit of Dynamic Drawing is that you can quickly sketch a point to get the approximate result and then use data entry to update to the exact dimensions, and coordinate values as needed.


Entities in Modify Mode

Final Entities


In the images above, we see entities which are still in Modify Mode, followed by those same entities after they are finalized.

Snap Increment

This function support the use of the snap increment when selecting the location of the entities. The snap increment allows you to get precise results when using mouse selection and helps to reduce data entry modifications.


To learn more, view Snap Increment.

To open Arc 3 Points - Center/Endpoints:

  • In the Entity group, of the Create 2D ribbon, click the down arrow under Arc, and select Arc 3 Points - Center/Endpoints.

The parameters display in the Data Entry Manager.

The Data Entry Parameters

Creation Option


Base Point

  • X - setsthe location of the arc center along the X axis.
  • Y -sets the location of the arc center along the Y axis.

  • Z -sets the location of the arc center along the Z axis.


  • Diameter - sets the width of the arc, as it would be in its complete circular state, from side to side.

  • Radius - sets the distancefrom the center of the arc to the circumference.

  • Start Angle - sets therotation angle at which the arc begins measured from the positiveX-axis.

  • End Angle - sets therotation angle at which the arc ends measured from the positive X-axis.

  • Other Half - allowsyou to choose the other half of the specified angle range.

  • OK - finalizes the function.

  • Cancel - exits the function.

Quick Steps - Arc 3 Points - Center/Endpoints

  1. Openthe function and click a snap point or anywhere in the graphics areato set the first point which will define the center of the arc.

    Youcan modify the snapincrement value or turn it off while selecting the points of thearc.

  2. Move the mouse pointerand click a snap point or anywhere to set the point which will definethe radius of the arc.

  3. Move the mouse pointer in the direction thearc is to be created.

  4. Click to set the angle range.

    Thearc changes from the Preview color to the Entity color and displayswith a greater line thickness to show it is the active entity.

  5. With Dynamic Drawing, you can update theData Entry parameters to modify the active entity, or you can continuesketching.

    If you continue sketching, the active entity is automatically finished.

  6. After updating the Data Entry parameters,to finish the active entity, you can either click OKor you can click the next point to begin creation of a new arc.

  7. Repeat this process of using sketching anddata entry to create arcs as needed.

  8. To close the function, click Cancel.

Related Topics

The CADOverview