I have tried the "Arc Tan to entities" with the "Through Point" feature enabled as suggested by John R. I got the first and second points established via the status bar. Then I specified and locked the radius in the inspector bar. The program insisted on a third point so I clicked on the arc between my two points. That is imprecise and I couldn't figure a way to do a local snap. Adding in the third point changed the radius by the amount of error in clicking, even though the radius was locked. Same thing with specifying beginning and ending radius angles, imprecise.
So one point would be how to enter this arc exactly. Another would be, after it is established, how do you go back and change any of the parameters, by coordinates, not clicking.
This is the most frustrating program. I guess spreadsheets are just plain easy. Anyway, much thanks to all for the help and comments. Establishing an arc of a certain radius between two set points is about day one-and-a-half or day two of high school geometry. Why is it so difficult in this advanced program?
Here's John's basic method in a little more detail:
1) Go to Insert|Point|Cross, and place one Point at each of your set point locations. (If you know only the coordinates of these locations, press Shift+Tab to access the x
field of the Status Bar and type the X coordinate of one point; TAB to the y
field and type the Y coordinate; press Enter to plant that first Point object; repeat for the second Point object.)
2) Go to Insert|Arc|Tangent to Entities; highlight the Radius
field of the Inspector Bar and type the desired radius, then click the "padlock" icon beside that field to lock the radius. Click the "Through Point" icon on the Inspector Bar (or right-click in the drawing and choose "Through Point" from the Local Menu).
3) Place the cursor on the first Point object and press V on your keyboard (an operation sometimes called V-snapping
); place the cursor on the second Point and press V. (If the center of the phantom circle you see on the screen is on the wrong side of the two points, press Esc
, V-snap to the second
Point object and then V-snap to the first Point.)
4) Final step is to define the endpoints of the arc: V-snap to one of the Point objects and then to the other. Which Point you snap first will determine which part of the phantom circle remains as your finished arc. (The arc is defined in a counterclockwise direction by default.)