Nodes AKA Construction Points-What the heck are they anyway?

Tuesday, March 24, 2009

This is one of those questions that I know...I do okay explaining it in person, but I'm lousy at putting it into the written word. Anyway today while reading my email I came across one of the best descriptions of this. I asked Jack if I could post it on my blog and he graciously said yes, so here is a GREAT description of what nodes/construction points are and their function.

"Yes, 'nodes' are the same thing as 'construction points' -- your
cutting file for any design basically consists of a list of
definitions for 'vectors', or lines that when followed, will cut out
your design. The nodes and lines define a 'path' for the cutter to
follow. The nodes are really the end points of these lines (straight
and/or curved). What you see on your screen are representations of
those lines, generated by the software, using the vector definitions
to 'draw' the lines that will later be cut.

Most of the time, these vectors will be connected at their end points
(nodes) and when cut, the blade will follow each line in a continuous
cut (i.e., path) without lifting the blade. To cut pieces that can be
lifted from the mat in one piece, all of the lines defining its
outline must be continuous, with no 'open nodes'. Some lines for cuts
within a piece may be intentionally 'open', such as slits, dashed fold
lines, etc.

When you use a command to 'simplify path', what you're really asking
for is to reduce the number of lines needed to create the design by
combining connected lines and eliminating the node between two lines
that are going in 'almost' the same direction -- thus smoothing out
some curves, making two lines into one straight one, etc. Always bear
in mind that even if they look clever, all computers are stone dumb --
REALLY dumb -- and any decisions about what nodes to eliminate is some
programmer's guess at what you might someday want. Sometimes they get
it right, and the file is smaller, cuts faster and better --
sometimes, combining two lines means eliminating a detail of your
design that you didn't want to lose.

When you magnify a design and see lots of excess nodes, there are a
number of ways to clean up your design, which can be tedious, but only
you can make consistent decisions as to what is a collection of excess
nodes and what is a critical part of your design.

Remember, every node generally represents a point where the cutter
blade will have to change direction, and sudden sharp corners and
reversals of direction will be hard to cut cleanly. Often you will see
spots on what should be a smooth curve or straight line where there
are two direction switchbacks that form a sort of 'Z' shape in the
line. Unless you really intended for this to show as part of the
design, eliminate them and your design will cut much cleaner.

Hope this sorts a few of your questions out...


Thanks Jack for sharing your computer knowledge to us and helping us understand better why and what we are doing.


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