Sometimes complex board outlines are created externally in a mechanical CAD application, then imported as it's easier to manage the details externally.  The problem is that this import can fail.  Why this happens and how to resolve it are discussed here.


The first issue, and a very important one, is that Easy-PC only handles circular arcs.  It doesn't understand complex curves where the radius is dependent on the position on the curve (such as an elliptical shape, for instance).  In DXF complex curves are normally known as 'Splines'.  Because these can't be imported directly, when the DXF file is created, these must first be converted to 'Polylines' - essentially a series of straight line approximations to the curve, which Easy-PC can import.  The errors introduced to the perfect curve with this approach are normally invisible even when zoomed in.

The second issue, and one which is more complex to tackle, is when the file for import doesn't contain a single continous loop, but is instead fragmented into sections.  This is the usual situation.  Again, it will prevent the DXF importing as a board.  Instead, the approach is to import it as a shape (actually multiple shapes) onto a holding layer where the import can be modified.

Once imported, to determine the fragmentation of the outline, click on any part whilst holding down the Shift key, <Shift+Click>.  One entire fragment will be selected.  Working round the shape will determine the extent of fragmentation.  Each of these fragments must be joined into a loop to complete the board.  The next issue is whether there are gaps or overlap between these fragments.  Direct inspection at a high zoom level will help, but fortunately there's also a utility which makes it easier.
Go to [View], [Dockable Bars] and open the [Shape Information] bar.  This works on any linear structure, including tracks, boards and areas, not just shapes.  You'll need to peg this open by clicking on the push pin icon.  Press <F1> to open the help for guidance on the best mode to use, though this is largely a matter of your preference.  You may need to adjust the width of the bar and the columns within for optimum clarity.  As well as showing information about the selected shape within the board profile, it can also be used to edit the co-ordinates.  Obviously this needs to be done with caution for curved sections, but where a curve meets a straight section, it can help with aligning the ends.  If perfect alignment is difficult, a small gap is preferable to an overlap, as when the ends are joined, there's a risk that a zigzag introduced by an overlap could cause problems.
Now we move to linking the fragments.  Firstly, go to [Settings], [Preferences] and open the [Interaction] tab.  At the bottom of the right hand column are the settings for joining shapes.  Adjust these if necessary.  Press <F1> for help with this if required.

Returning to the outline, use <Shift+Click> to select one fragment, then <Shift+Ctrl+Click> to add an adjacent fragment to the selection.  You can select multiple fragments - the function is not limited to two, but it's probably best to join the fragments progressively rather than attempting all at once.  Having selected multiple fragments, right click on any part of the selection and choose the entry [Join Open Shapes].  This should link the fragments together.  There is one important constraint on this function.  All shapes to be joined must use the same line style, but it's only rarely that the case that the line style will vary between fragments and need adjusting.  You can check this function has worked by using <Ctrl+Click> which should now select all the joined parts.  Continue until the board outline is complete.

Select any part of this complete outline and open the properties (Right click then [Properties] or use one of the available shortcuts).  Check the box for 'Closed' but leave 'Filled' unchecked.  C'lose the properties, and again right click, this time selecting [Change Shape Type].  Use the dialogue to change from 'Shape' to 'Board'.  When you close the dialogue you'll see that the shape has indeed become the board you wanted, and will now show as 'Board' on the status line.