Freehand > 3D polyline

Drawing freehand shapes

  • A curve entity contains multiple line segments but can define and divide a face like a single line. Although you select all the segments in a curve entity at once, the SketchUp inference engine displays point and edge inferences for each segment in the entity.
  • A polyline entity doesn’t generate inference snaps, create faces, or affect geometry in any way. You create a polyline entity only if you hold down the Shift key as you draw with the Freehand tool. Polyline entities are thinner than curve entities.

Huh, who knew? :slight_smile:

Thinner in what sense, I wonder?

Then what is it for?

I quoted from official “help.” As far as I can remember from the very beginning it is described this way.
Of course, depending on what style you use, the appearance of “lines” can vary.

Also I quoted from the official help.:
decorate your model.


Now, that is an interesting notion: I can’t say ‘officially’ that we feel this entity is a good way to decorate the model. I’m still hopeful this thread will catch the eye of someone who has figured out a reason for this polyline.

1 Like

To me it seems that the polyline doesn’t register as a “profile” while the “curve” does.

I don’t find a way to use the polyline to create faces or anything so, perhaps, it is only good for “decoration”. In that case I don’t see a reason for it.

1 Like

“decorate the model” as in draw chat bubbles or call-outs and highlights perhaps? Similar (in some ways) to 2D text labels.

And I’m still hopeful I will wake up in the morning and leap out of bed feeling fresh and rejuvenated and ready for the day ahead.


Erm, it is a bit late for that even here in Finland. Isn’t the morning almost there already?

It’s actually come and gone already here, and sure enough, much like the polylines, I flopped out of bed onto the floor and gradually dragged myself to the coffee machine with no coherent purpose other than existence.
9.30 am

1 Like

Huh… learn something every day, just drew my first polyline ever. I guess maybe I might use this as a markup tool for notes on an existing model. Like sharpie circles around areas of a paper print but without the danger of altering the existing model, or confusing the inference engine. Not sure I really need that but… maybe in a collaborative team setting? Long stretch.

I am certainly now going to draw squiggles all over my colleagues models when they are not looking. Nice big scribbles that they can’t select and can’t erase… perfect. :smile:


With a standard length 3D Polyline component and the right short plugin one could iterate through a model … :

  • select (part of) a model
  • use the aforementioned plugin to iterate through the selection to…
  • replace all edges in the selection with the 3D Polyline component, thereby scaling this component to the lengths of these edges
  • This will result in a visual reference on which the inferencing engine has no influence.

3D Polylines can be colored independently of whether ‘Color by Material’ is on/off for edges.

3D Polylines (using the standard components) can also enrich a model with no interference of the inferencing engine. (centerlines of shafts, maybe even converted 3D text to 3D Polylines etc.)

I know it can be cumbersome to use 3D Polylines but with the right plugin they could be tamed.

Here is a group (not yet a component) that has a standard 3D Polyline of 1m length.

@sdmitch once created a short plugin that converted (replaced) edges with 3D Polyline components.
Unfortunately I don’t have it available anymore. And it was at the time thatSketchUp 8 was the up to date version.

3D-Polyline length 1m.skp (211.8 KB)

Also think of a “pencil”-plugin that lets you pick among multiple colored 3D Polyline components and use the pencil to just draw in modeling space. No conversion (replacing of edges) but drawing directly as if they were edges. Wouldn’t that be something.


Hi @Mark , please don’t let the developers kill the Freehand tool and at the very least keep the 3D Polyline available for plugin writers. It has tremendous potention.

(If only I had the knowledge to code Ruby or work with someone to develope a neat pencil plugin!
I’m all in for discussing options and features for a 3D Polyline pencil tool and its usefulness in modeling)


A simple example of a reference circle consisting of 3D Polylines, (standard R=1000mm, can be scaled) that does not interfere with your modeling operations, no snapping to… So it is only a visual reference)

(Unfortunately a ‘Construction Circle’ tool is still lacking in SketchUp)

3D-Polyline length 1m (1).skp (226.9 KB)

1 Like

@Wo3Dan Thanks for these posts, Gerrit. This is exactly the kind of detail I was hoping to suss out. Using the API to transform geometry into polyines so that it cannot be inferenced against was not my radar. For what it’s worth, some of the ideas you suggested for using polyline entities as illustrative or annotating overlays are part of the discussion we are having around the Freehand tool.


Using the API is something some of the plugin developers (@TIG and maybe also @thomthom?) have been asking for, a way to get hold of the 3D Polyline entity. Now the only cumbersom way is conversion of edges into a scaled small chunk of a standard length 3D Polyline by replacing them.

It strikes me that the entity 3D Polyline exists but for all I know no one ever, not even from SketchUp, explained them being in the program. Other than roughly tracing some reference curve and then exploding them. But they have far more potention as staying 3D Polylines if tamed.

SketchUp does not support components from being (temporarily) excluded from the inferencin engine, unfortunately. Maybe this could be done in future by giving an extra attribute, as a simple switch, to components: engine = true / = false meaning the engine finds them / ignores them. Why do I bring this up? 3D Polylines are ignored completely by the inferencing engine. They are the only way to somehow overcome the aforementioned components being ignored.
Other programs may use layers to switch off 3D geometry from being seen by the drawing tools, no snapping. In SketchUp layers are different.

I’ll try thinking of some examples in which the 3D Polyline could also be useful. Maybe hatches in section cuts of SketchUp Solids. You see them but they aren’t there to interfere.

Playing with a simple model as reference, no reason in particular:

3D pol-kleuren 2meter.skp (1.3 MB)

1 Like

And so it was done, which I had no forewarning … because this topic is in the wrong category.

The Corner Bar is not supposed to be about SketchUp products and so I have this category muted to cut down on the “noise”. And did not see this topic revival when it happened.

  • Nab, Thank you for moving this to the SketchUp category. (APR 2023)

Regardless, I am not opposed (belatedly) to the simplifying of the Freehand tool.

I dislike when a single tool has diverse uses or output. What usually happens is that these tool output products are lacking robustness or options.
Examples, in my opinion, are the Tape Measure tool both taking measurements and drawing guides with limitations. (We could use this separated into a better Measurement/Query tool and a fully robust Guide drawing tool.)
I also put the Eraser tool into the same group. I’ve never been comfortable with using Eraser to just Soften or Smooth edges. Cramming both erasing and softening into one tool complicates the tool and forces use of tiny cursor overlay icons which are not always intuitive.

So @Mark, because I did not see this topic revival, I could not at the time (FEB 2021) point you toward a “PolyLine / PolyPath” Feature Request that had been discussed for 4 months, a year previous (JAN…MAY 2020) to your reviving this discussion.

In this discussion, after some confusion by some with curves drawn with the FreeHand tool, we got down to talking about all the nifty things we could do with a true poly path tool that creates non-geometric 3D pathways for both annotation (with and without stipple), tool enhancement (with and without inferencing) and extension supplementation.

1 Like

fair point. moved to Sketchup category. I think the thread evolved from a simple corner bar discussion to this.

Thanks for moving it ...

But the OP asked a question about an existing SketchUp feature.
The Corner Bar is for “non-SketchUpy” discussion.