Construction Circle through Two Nodes, with One Tangent

1. Activate the mode of creating circles passing through node.

2. Select a first 2D node for the circle to pass through. A node may be selected in one of the following ways:

•Press or <Enter>, while the cursor is within drawing window, in order to select a node nearest to the cursor.
This way of selection works, only if the node is selected before selecting any other elements.

•Move the cursor over the desired node, using object snappings, and press or <Enter>.

•Move the cursor over an intersection of construction lines or a characteristic point of a graphic line, using object snappings, and press or <Enter>. A connected 2D node will be created automatically at the specified point.

•Activate the following automenu option:

If the option is activated via keyboard, then the node nearest to cursor gets selected instantly.
If the option is activated via mouse, then you have to additionally press within drawing window for selecting the nearest node.

3. Select a line for the circle to be tangent to. You can select a construction line (straight or circle) or a graphic line (straight, circle or circular arc). A line can be selected in one of the following ways:

•Move the cursor over the desired line, using object snappings, and press or <Enter>. In case of selecting a graphic line, a coinciding construction lines (straight or circle) is created automatically, and the current circle is based on such construction line.

•Activate one of the following automenu options:

If the option is activated via keyboard, then the construction line of the corresponding type nearest to cursor gets selected instantly.
If the option is activated via mouse, then you have to additionally press within drawing window for selecting the nearest line.

4. Set the desired tangency configuration, if necessary. Use the following automenu option for switching between possible tangency configurations:

Tangency configurations are also switched automatically, when moving the mouse, depending on which configuration allows the circle to pass closer to the cursor.

5. Select a second 2D node for the circle to pass through. A node might be selected in one the ways described above.

Second, third and fifth steps can be performed in any order. If the selection starts with selecting a node, then the first step is mandatory. If the selection starts with selecting a line, then it doesn't matter if the mode of creating circles passing through node is active or not - you may start the construction in the mode of creating circles centered at node as well. If a line is selected last, then the tangency configuration switching (fourth step) is not available.

Example of creating a circle tangent to a graphic circular arc

Example of creating a circle based on the same elements with different tangency configuration

 

After creating a circle the command returns to the initial state.