SketchUp Bezier Curvature Control



Hey everyone. I have tried most of the bezier curve plugins for SketchUp in the last hour but can’t quite find something specific. I’m looking for a tool that would allow me to add a point to a curve and edit the point itself, just like in LayOut and Illustrator.

I’ve tried the plugins from Fredo, Jacob Samuel and others. I need this curve to pass exactly through those construction points for the logo. The closest is Fredo’s Catmull Spline but it doesn’t allow to smooth the points like in the examples of LayOut above (with those blue “wings” with points at the ends).

Does anyone perhaps know if such a tool exists for SketchUp? Many thanks in advance.


One of the bezier curve extensions does it, via an “Add point” item on the right-click context menu. (I don’t remember which one.)


Thanks for the info, Dan. I guess I will have to re-install every bezier plugin and look for that feature.


I just played around a bit in SU2015 where the old @last plugin and Fredo’s updated edition are both installed.
Fredo’s is clearly superior, and can add control points by double-click.

But, back to your OP, you can add segments via the VCB, but all vertices are equidistant. Ie the curve is equally divided.

To do what you want you might have to choose polyline. (Not sure, but bezier curves are controlled by control points, not by individual vertices.)


Thanks again for having a look Dan. I tried and tried but there really is nothing like a curvature control with anchor points for SketchUp. I ended up using Fredo’s Classic Bezier Curve and approximated the curve as close to the points as possible. Still, would be a good idea for a future plugin I think. Thanks for your time. Appreciate it. :slight_smile:


I used Fredo’s Classic Bezier tool to trace your curve. I started out with 5 or 6 control points and roughed in the curve. Then I added more control points as I fine tuned the curve.

Did you catch that you can add control points as you are editing the curve?


Well I’d think you could use ThomThom’s Vertex Tools if you absolutely had to be dragging vertices around.


Hey Dave. Yes, that is more or less the exact way I edited mine.

Yes I did. The thing is in my original post I’m asking about adding points onto the curve itself. Something like the Pen Tool in Photoshop. Difference is that you work by editing the points. And the points are filleted. In my example there’d be 6-7 points to work with.

I haven’t used the Vertex Tools. I’ll have a look at it, thanks.



Oh wait! I was correct Fredo’s Polyline option also does what you wish.

You can start with a Bezier Curve, and convert it to Polyline, then go into edit mode and drag vertices around, double-click anywhere to add vertices.


Yes. I know.


@DanRathbun, I tried the Polyline option this morning, like you suggested.

I can add points to the curve now and move them around. However the points have no smoothing handles for filleting like in the gif file above. Perhaps I’m missing something?


You are getting a simple polyline, not a spline (i.e. no smoothness constraints at the knots, as you can see from the sharp corners at some of the knots).

The smoothing “handles” imply a particular algorithm to solve for the spline parameters (set the tangent value at each knot), so it is possible to add them only to implementations that use that method of solution.


Is there documentation of Fredo’s extension ? (That would be the best place to start.)

Of course a polyline will not act like a curve.

If it turns out that his extension does not do exactly what you wish, the best course is to file a FR for his extension. (Most extensions at SCF have a discussion thread in the Developers forum.)


I haven’t been following this but it may be worth pointing out the Fredo gives you a huge amount of edit options. For example somewhere in it all you have the option to smooth a curve above, below or through points. It might be part of Curvizard.


@VahePogossian, the answer is yes. He has links to quick ref cards (in PDF format,) and a downloadable Tutorial and a video tutorial (in the root post of his plugin thread):


Did you try his F spline, it uses actual control points on the curve itself vs the " normal" control point approach?



Thanks for the link. I scrolled through all the available materials.

I’m having trouble deciphering the SCF. Does it stand for “SketchUcation Forums”? I think a feature request for point handles wouldn’t hurt and would be a beneficial addition to the plugin.

@Box @mac7595

Thanks for having a look guys. I tried the Curvizard and the F-Spline method. Attaching a comparison shot:

They’re almost identical and the curves do pass through the points. Though in the Curvizard variant, for example, the curve also crosses the tangent border in some places, which is bad. Further fine-tuning can only be approximate.

I have this rough sketch of what I have in mind as a curvature point handle control plugin. Could someone tell me if this is the correct place to contact Fredo for a feature suggestion?


SCF = SketchuCation Forum. :wink:


SCF = SketchUcation Community Forums

But it has grown to have much more than forums over the years, and so is now officially known as SketchUcation LLC.

Yes, that would be the best topic thread (unless he gives a link to GitHub repo Issue Tracker.)

I do not find any threads in the Developers forum (re BezierSpline) newer than 8 years old, and they are about specific issues. It is not worth re-opening any of those old threads.


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