DXF Start node

destroyed work due to ‘move’ lines.

The problem

If you are an experienced Foamcutter user you will likely have run into this problem : Your machine cuts your shape just perfectly and just when it is done your hotwire makes a strange move cutting your work in half, or …… you hit start to cut that beautifully styled letter “A” and your hotwire first cuts a diagonal straight through your new sheet to rebelliously start at the opposite site of where you thought it would start.

Why it happens

After your hotwire machine has departed from the 0,0,0,0 coordinate to start cutting your new shape, it first has to move to the starting node on your shape. This starting node does not neccesarily line up with the 0,0,0,0 coordinate. If the start-node lies at the other side of your object your hotwire will destroy your sheet before it even starts cutting along your shape path. Subsequently , if your machine is set to “go home” after it is done cutting a shape, and the last node lies on the wrong side, it may cut your work in half.

notice the blue move-line below that cuts right through the shape we want to cut

notice the blue move-line that cuts right through the shape we want to cut

Here is the shape as it shows in inkscape (the free vector drawing program)

Visualise the path

In inkscape go to : extensions > visualise path > number nodes

Inkscape now shows the starting node and the order of things. Notice in the image below that on the top middle of our shape we find node #1 (start-node) and node #13 (end-node) that in reality lie on the same spot. This is where your hotwire starts and ends. If your machine zero,zero,zero,zero point lies bottom left (like in our first picture above) it will cut straight through to node#1 and then will follow on to node #2, #3 , #4 and so on.

rotate your shape

remove the middle node (node #1 )

notice we only have 12 nodes left and the start-node now lies bottom left.

hotwire no longer cuts through your shape.

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