Closing Part Contours

If you are trying to output but are finding any of the following:

  • Multiple entries on Parts or Contours
  • Parts cut the wrong way / wrong side.

Often this is caused by breaks in the drawing.

Breaks in a contour will mean that the contour will not be cut correctly, and can potentially confuse the inside / outside logic meaning it could cut as an outside contour when it should be an interior contour, or vice versa.

Thankfully there are a few ways to fix this. The simplest way is to redraw the offending section. However, for complex drawings, with thousands of entities this is often quite difficult to accomplish. So here are some steps to take to repair your drawing in FastCAM as much as possible before you need to redraw.

1. CAD Compress

CAD Compress is a great tool, not only for reducing the number of entities but for helping the later closure techniques to work optimally. A drawing that is complex, with high entity count has a higher chance of having a break in one or more of its contours. Here is a guide on how best to use CAD Compress:

2. Identifying Breaks

Once you have run a CAD Compress over the drawing, usually the next thing to do is Identify where the breaks in the drawing reside. There are a couple of ways to do this.

Parts & Holes

The quickest is to use the View > Parts & Holes Option:

Raw Drawing

The Drawing with obvious breaks on the 3rd and 6th Rectangles

Parts and Holes

The drawing with Parts & Holes on. You can clearly see the two unclosed shapes show differently because they cannot be properly identified.

Verify Contour

However this may not be available for your version of FastCAM or isn’t appropriate for your drawing if it is too complex. So you can identify individual contours using Verify > Contour

Then click on a contour & check the closure:

Gold & White = Closed Contour

Red & Blue = Open Contour

NOTE: Where the Red and Blue lines meet, or end, is where the break in the contour exists

There is also a Blue Box that will appear usually at the bottom of the screen, if you hold your mouse in place, it will tell you relevant information about the contour including the closure, area the contour encloses, area limits, etc.

3. Closing the Contours

Fix Joints

Firstly you can try the automated closure option, which is Utility > Fix Joints

This will attempt to fix the unclosed paths. 

CAD Clean

It could also be that you have some lines drawn on top of one another. For this try the Erase > CAD Clean method:

However, for drawings that are of an artistic/graphics nature, this can often pick up valid entities and remove them. So use this one with a bit of caution. CAD Compress, the first option, should also be of assistance with this problem.

Redraw the Section

If you have come to the point where the above automated tools cannot solve the problem then you likely need to redraw the offending sections. This is usually not difficult if the drawing is not too broken. If there are too many breaks however, it can often be better to revisit how the drawing was originally created and see if it can be remedied there.

As for redrawing, have a look at the FastCAM Drawing guide here:

What you need to do is delete the offending section, either using the Trim > Smart Trim

Or use the Erase options:

You can also put down some points to help redraw the area so you can retain the shape if the break is in a detailed area:

Then once you have deleted the area, and are ready to redraw, you can redraw with Lines or Arcs


Use the Line option

Then Right Click and select Control Points

Then click on the control points that need to be the ends of the line:

If you don’t know where a relevant control point is, use the Control Points button:


For arcs you have a few more options. If you put points down along the arc, then the best option is to use Arc > Arc

And Start, point, End

The other options are also very helpful for certain applications, but it is up to you which will be best at redrawing that particular section.

Again, you need to make sure you are in Control Point mode however when defining the points to make sure the points are correctly lined up:

4. Finally, if all else fails...

Please feel free to send over a service email from The FastCAM Drawing Editor with your drawing loaded:

We will get back to as soon as we can!

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