# Thread: Average of curves

1. ## Average of curves

This may be a dumb question, but I have not been able to find any references in the manuals. So I figure I would ask it here.

Running Rhino3d 4 sr 5 on a pentium 4, 3 gig machine.

definition: curve = the result of the optically scanned in object
line = the result of replacing all the optically scanned in line fragments with one "best fit" line.

lets say I draw a shape on a piece of paper and optically scan it to a graphic file (jpen, tiff, etc.). Convert it to a dxf (with a raster to vector converter like winTopo) and import the dxf onto Rhino. For simplicity lets say this curve is a straight line (the actual curves are much more complex, but this is fine to illustrate the question.

Because the line on the original paper has a finite thickness the resulting curve imported into Rhino will be a set of very small curves and fragments of curves that describe the line I want. These curve fragments give the scanned in curve a finite thickness (think of having the line drawn by thousands of tiny hairs forming a mesh of the proper length and a thickness like that in the original pencil line).

Is there any way to select the curve and then have Rhino calculate a single line, i.e. the best possible fit to the curve?

WinTopo does offer curve thinning, and I do thin the original as much as possible without having it totally disappear when it generates the vectorization.

Thanks,
Steven

2. In the event that any one is interested, I checked with McNeel central command on this question. No such tool exists for anything more complicated that a straight line of circle.

3. Because the line on the original paper has a finite thickness the resulting curve imported into Rhino will be a set of very small curves and fragments of curves that describe the line I want. These curve fragments give the scanned in curve a finite thickness (think of having the line drawn by thousands of tiny hairs forming a mesh of the proper length and a thickness like that in the original pencil line).
I don't really understand this. A raster to vector software (a decent one in any case) should give you a vector - with no line thickness. That is why you are doing this in the first place. If the R-V software is giving you a bunch of non-connected teeny line segments that create a virtual "line width", then I suggest that either it is poor software or you haven't got it set right.

R-V conversion will rarely give you really nice curves but it should give you something that IS a more or less continuous curve (if the original is reasonable). You may need to fill in gaps, clean up the curves, but that's what Rhino is good at doing with its commands like rebuild, etc...

You might want to try something like Vector Magic. It costs, but it's one of the best out there. --ch

4. I may be misunderstanding your question, so please forgive me.

In rhino, there are lines and polylines. Polylines are multiple curves joined into one line, that once exploded, will break down into individual segments.

A polyline can be converted into a curve using the "rebuild" function. If your small lines are all touching (end to end) , you could join them, and then "rebuild" them to form a single curve.

If this does not apply, feel free to put up a picture of what you have in rhino. I would love to take a look.

Rob

5. Here is his line that he scans.

Here is the scaned line, vectorized zoomed in on.

An outline of the line.

The previous poster would be correct to get this function out of the conversion software.

6. Hi Rob,

Actually it's more like this (vectorization done in WinTopo and attached here). If I was just seeing what burrman posted I would be ecstatic I did however just pick up a copy of vector magic and it is fantastic. it appears to have solved the issue I was seeing.

Thanks all.
Steven
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