[Extension] FredoSpline - Bezier, Spline, Polycorner, Polyline division

FredoSpline is a suite of tools dedicated to handling a variety of curves based on control points.

  • Bezier, Classic and Nurbs
  • Fit Spline, local and global
  • Polyline with division pattern
  • Polycorner, which are polylines with configurable corners at vertices

FredoSpline - Toolbar

FredoSpline is published at Sketchucation

Since v2.0, FredoSpline is a paid plugin under a Sketchucation license.
Prices are indicated on this page. You get a 40% discount if you are a Premium member at Sketchucation.

Here is a video presenting the main features


Looks very nice, @Fredo6! Your new extension has a large set of features, which were presented very nicely in the video.

Fredo BezierSpline is one of my favorites (polyline segmentor… Love it!!). With the release of FredoSpline, should it be considered deprecated?


Not deprecated. I maintain it, although it would likely not have functional evolution. Kind of same situation as RoundCorner and FredoCorner.

I suggest to keep BezierSpline, just in case if FredoSpline has problems, and also for those who are used to it and find it simpler.

I wish every developer produced videos to explain their extensions like this.



Please note that FredoSpline 1.1a does not work on MAC. It either crashes or does nothing.

As I have no Mac, I am struggling to find out the cause.

I just sent a BugSplat ( Crash Report #20151) to Trimble with a note to contact you if they can figure out what caused it.

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I just published FredoSpline v1.2a which hopefully should fix the crashes on Mac.

This goes along LibFredo6 - v10.2a, which is advised to install too.

Note that there may remain some problems. Thanks to signal them.

The link says the extension is not published yet. There may be an issue at sketchUcation?

I installed the update about 45 minutes ago via the Sketchucation Tool.

Maybe you got in ahead of Fredo doing something more? I don’t see this version on the sketchUcation store now and clicking the link in his post yields this:


Just now, though.
Screenshot - 4_29_2020 , 8_57_08 AM

Just hit the Extension store. Two successful Fredo updates, Spline and Lib

Yes, it now worked for me too. The plugin store must have been delayed for some reason, but now up to date again.

Edit: And so far on initial tests it hasn’t crashed on my Mac!

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Good news. Which OSX do you have?

Also, do you see problems of performance?

I have macOS 10.15.4 Catalina. I didn’t do an extensive test, just a quick trial of what had caused a crash before (simple traditional spline), but it seemed to perform fine on that. Something is interfering with changing the active model tab right now. Do you have an observer that might do that?

Strange. I don’t know what it can be and did not even know you could change the model via the Ruby API. The only observer I used, very briefly, is to catch Undo versus Redo.

Could you describe more what you observe (I don’t have a Mac, so I can’t figure out).

By the way, I recommend you upgrade to LibFredo6 10.3a, just released, because there is a problem that affected Curviloft, curvizard and the Convert tool of FredoSpline.

I don’t know that it is due to your extension, just that’s the most recent thing I installed.

On Mac, SketchUp can open multiple models in the same app. It can show them as tabs across the top of the SketchUp window, and I can shift from viewing one model to another by clicking the tabs. Sometimes when I do this, the view changes momentarily to the tab I clicked and then jumps back to the prior one. It is inconsistent, though. I haven’t found some situation that will trigger it consistently. So just grasping at straws that some observer may be guilty.

OK. I see.
FredoSpline does nothing special that my other plugins would not do. Actually there is little dependency on the platform (the crash was due to a corrupted PDF cursor file, first time I use SVG/PDF for cursors).

FredoSpline is an excellent extension which is a great addition to SketchUp- Thanks you so much Fredo6. Its filled with so much capability but for furniture design I use either the Bezier Classic or the Local Fit spline

I can use some help with the following:

  1. With the Bezier Classic, if have only a start point (starting on the end of a straight line) and an end point with a single control point, is there an indicator when tangency is achieved ?
    I have tried moving the control point along the straight line but no indication. I thought maybe the bezier curve would turn cyan.
  2. Is their a way to have a point of the Bezier Curve stop at a fixed point like a guideline. Take an example, (see below) If I want to draw a curved table apron that is 2 1/4" wide with a curve that is 13/16" up at the center. Currently I start and end the Bezier Curve on the apron and move the control point up by eye so the center is close to the 13/16 guideline. I would like to know the curve is exactly on that guideline. So its a Bezier Curve with a fixed local point.