Centreline Cross

This tool draws a centreline cross in arcs, circles, ellipses and elliptical arcs, as requested by Husky and seconded by J-J.

In the options toolbar there are two input boxes labelled X and Y.

The value in the X box refers to the horizontal line of the cross, and the value in the Y box refers to the vertical line of the cross. If you leave the Y box empty then the value in the X box is used for both lines of the cross.

To the right of these boxes is a drop-down combo box with two options, 'Extend' and 'Length'.

Extend mode is equivalent to 'overshoot' in Husky's diagram. A positive value will extend the lines past the circle. A value of zero will draw the lines to meet the circle. A negative value will draw the lines short of the circle. If the length of a line evaluates to zero or less than zero, then that line is not drawn.

Length mode draws lines with the specified length in the X and Y boxes. Again, if Y is empty then X is used for both lines. Also if the length of a line evaluates to zero or less than zero then that line is not drawn.

To the right of this is the 'Orient' box. This specifies the angle to draw the cross at. You can enter a value between 0.0 (default) and 180.0. A value greater than 180 would be the same as that value minus 180. (i.e. 181 - 180 = 1, so 1 will produce the same result as 181. A value of 91 will not produce the same result if the lines are of a different length.).

Ellipses and elliptical arcs have an angle associated with them, so the cross is drawn at that angle. That angle becomes the base angle to which the orientation is added. (i.e. if an ellipse is drawn at an angle of 45 degrees, then the cross is drawn at 45 degrees. If you then set an orientation of 20 degrees, the cross will be drawn at 45+20 = 65 degrees.)

The lines are drawn on the current layer so they can have different attributes from the arcs, circles etc.

Also the command does not check if a cross has already been drawn, so if you click on a circle more than once then you will have more than one cross.

If you wish to undo a cross use the 'undo; option in the 'edit' menu. Right clicking terminates the command. If you select an entity that is not an arc, circle, ellipse or elliptical arc, then a warning message is shown.

The shortcut for this command is CS.

The attached zip file contains the 'Cross' sub-directory.

Extract this to the 'scripts/Misc/MiscDraw' sub-directory, and you'll find the command in menu 'Misc->Drawing'.

Hope this is what you requested. I have only done limited testing of this, but it appears to be working correctly. However if you do find a bug, let me know so I can fix it.