What is there to know about 3D Polylines?


#1

The question is simple, but are 3D Polylines simple, i.e. manageable?
For instance, can 3D Polylines be controled by plugins? And what are they used for?
How do you apply them if you do?

(this question has also been asked in SketchUcation)


#2

You mean that odd entity type you get when using Freehand tool and hold down Shift?
I don’t know the story behind them - but the API doesn’t provide any control over them.
@tyler_miller - got the history behind this oddball of an entity?


#3

Yes, that’s the one. Rich O Brien (at SketchUcation) gave a nice description of the tool: “greasy pencil”. Although you can tackle it with basic SketchUp, keeping your hands clean. So it does have some use, but unfortunately it can’t be (as you say) controled directly with Ruby.


#4

Four years ago @Gully_Foyle and I were lamenting the lack of a thin line type for GD&T annotation.
I wondered if there was a way we could use the thin 3D Polylines.

http://sketchucation.com/forums/viewtopic.php?f=323&t=35384

The problem is you can’t draw a straight 3D Polyline or convert an Edge to a 3D Polyline.
They’re hard to select too. A window selection works, but a crossing selection will not.


#5

A selection window around its tail end, i.e. where you finished drawing the 3d Polyline, does select the “greasy line”.
I would like to hear the story behind 3d Polyline entities. No-one seems to know how to properly use them. You can’t snap to them although that can also be an advantage.


#6

Is there any news yet?
Some related questions that may expand the use of these 3D Polylines:
Can edges be converted into (i.e replaced by) components containing one single edge per component. One “single edge” component with scaled versions replacing all the edges in a selection.
Next step would be to replace this component (and all its scaled instances by a “single segment” 3D Polyline component, scaled likewise per edge component. This component with standard length, say 1m is already an “In Model” component.
This would allow replacing a wireframe by a 3D Polyline version that doesn’t interfere with the inferencing engine and serves as a visual reference.
Some examples:
-1) visual marks in a model, easy to spot (whether accompanied by a guide point or not) each with its own color, even with edges colored all the same.
-2) visual referens of axes in a different color (for color blind people)
-3) symbols that are visible in the model but don’t interfere with what you are modeling (no snap to)
(Mike Lucey at SketchUcation once mentioned working on symbols, using edges and faces. But the cursor keeps snapping to real geometry). example: 2D vegetation.
-4) accurately dimensioned (scalable) visible circle or curve, not interfering the inferencing engine.
-5) though limited, two styled in the model, say straight 3D polylines plus a sketchy style.
-6) maybe some other options.

If replacing edges for “single segmented” 3D Polylines through plugins as mentioned above isn’t possible, -1) trough -5) is still possible but very laborious, some more than others.

edited:
-6) completely transparent hatches opposed to faces textured with hatches.
-7) (3D)text, visible though not in the way when modeling.