Translations:Engine Block Tutorial/37/en

Laying Out the Head Bolts
Now that the proper plane projection and view is set up we add 2d drawing elements in the same way we added primitives. Click the Add Circle button and move your mouse around in the 3D view. You then need to tell FreeCAD the XY location for the center of the circle, and the radius, for both of these measurements you can either enter them with the mouse (following the instructions in the bottom left status bar), or you can type in the values in the text entry boxes that appear above the tree view. Go ahead and add a couple random circles on the top of the engine, as well as a few not on the engine, i.e. just out in the empty space surrounding your view of the engine. After you have done this, rotate the camera around the top of the engine block and look at the circles you drew, notice how they are "flat" in the plane we projected them into and this plane lines up with the top of the engine block; this will be important when we extrude the drawing to shape the engine. Now that you see how to add 2D elements you can delete the test circles you added and we will start entering the actual head layout. Note that if your circle disappears inside the engine block, your drawing projection plane is not properly set to XY mode, offset 110 mm.