Reduce nodes feature

neil said:

My question is, does the 1-100 scale refer to the percentage of nodes that are removed, and what's the reason it won't go beyond a certain percentage?

Is more complex than this. Is relative to the "smoothness" of the image, but there're several values to consider. Change if each node is cusp, symmetric or uniform, the distance between nodes and between handles, and also the angle of each nod's handle, the extension and direction of each handle. I't a very complex job, but for this reason is only visible as a simple slider.

Ahhh -- you aren't actually on "reduce nodes" -- the UI is VERY misleading and should have been changed. The two side by side items, "reduce nodes" and the "slider" beside it actually are totally different functions. Each has its own use.

The reduce nodes button is, well, the reduce nodes button. Pressing it eliminates all nodes, using a fixed value, that would not change the curve. Its functionality was greatly enhanced in, I think X3, it might also be modifying adjacent nodes to those dropped so that they take up the slack, so to speak. In any event reduce nodes has a remarkable ability ( X3 and later) to eliminate nodes and make no discernible change in the curve.

The slider beside it is the "smoother," a totally different function, as Ariel describes. The smoother, even in the lowest level, does change the appearance of the curve. Taken to extreme cases it can change some  complex curves either into a straight line or an ellipse.

Going way back in history, there was a time when reduce nodes had a tolerance factor. Any node which, in eliminating it, would only move that point by the tolerance simply vanished. Somewhere, perhaps Draw 11 or so, the tolerance factor vanished and the function became almost useless. Then, I think in X3, the reduce nodes became very powerful, apparently a new algorithm. As mentioned above, more nodes disappeared with it and the accuracy became phenomenal.

Summary: in X3 and later, if you need to keep the shape of the curve, use the reduce nodes button; the appearance of the curve won't change (in almost all cases). If you want to smooth the curve, use the smoother to the degree wanted; the curve will change visually, ranging from subtle to dramatic.


Ripcord wrote:

Hi,

I use this feature often, but I'm not sure I fully understand it, because I don't know what the number setting (1-100) refers to, and I can't find an explanation of it in "help".

neil said:

Sometimes when I power trace a bitmap there are so many nodes that i spend too much time getting rid of them all...It would be nice if I could get the "reduce nodes" feature to remove more.

One of the macros in this commercial package allow you to reduce nodes on numerous complex shapes at once such as clipart, where there are too many nodes. Even works on shapes inside groups!

You can define the Threshold in the VBA Editor. This allows you to decide how aggressive the algorithm should be.

There is also an related addition to smooth nodes on multiple shapes at once too. As Paul explained, the shapes will have reduced nodes, but can also change in appearance by becoming .. smoother. ;-)

neil said:

Sometimes when I power trace a bitmap there are so many nodes that i spend too much time getting rid of them all...It would be nice if I could get the "reduce nodes" feature to remove more.

Neil. You've got some very good explanations of the Reduce Nodes and Curve Smoothness functions, as well as a link to a great tool for making node reduction easier.
One thing that I come to think of is; Why don't you try to manually trace the objects instead? Manual tracing, using the Pen or Bezier tool for example, will create much simpler objects. It is slower but on the other hand you don't have to spend so much time cleaning up and tweaking the curves afterwards.