Polyline segment drawing at relative angle

During drawing polyline I want to place segment at angle relative to the previous segment. I can’t find a way to do it.
I was looking here for the answer here but without luck: Accurate drawing | Rhino 3-D modeling (mcneel.com)

If I type <45 I can draw lines at 45 deegrees but relative to the current CPlane, not in an angle to the previous polyline segment.
Is there some symbol or drawing mode I am not aware of?

I know this might be a lame question but I really can’t find an answer to it.

not with polyline, but why not just using line with option angled at that point? if you have a bunch which you might want to draw continuously use the star symbol in combination with line → *line that will repeat the line command till you end it. in the command switch to angled by entering a then draw the angle and proceed, or proceed with the polyline command.

i have the repeat line bound into an alias with '_Repeat Line which involves the repeat command as you might know.

Thank you for sharing good tips.

I think I missed it because I wanted to draw polyline, didn’t know that Line tool will be more suited to draw polylines.

Anyway, Angle option in Line command requires a lot of clicking.

To sum it up:

  • Drawing polyline segments at angles is not where it logically should be - as an option of Polyline drawing
  • It takes some knowledge just to do this supposedly easy task (repeating) and post-processing (Joining) to created segments
  • There is no visual feedback as with SmartTrack
  • You need to be carefull when typing angle, because you can’t change it in the middle of the command, while normally when drawing lines you can change things
  • You need to be carefull about the side, at the same start one must choose negative or positive number, if you are wrong, start again

Is this angle drawing system something that can be discussed? There are some good stuff when drawing lines like SmartTrack, but I think some things should be a lot easier to achieve. Please I would like to know your opinion @pascal

can you describe a typical user case where you would need polylines to be able to make a continuous amount of special angles while drawing on regular basis?

i believe that special angles are rather special cases, not something i would need to set after each line.

30 degrees angle from a given line is that special? I can make special angles according to construction plane very easily (typing e.g. <34) but I can’t easily change direction of drawn polyline like that. How would approach drawing this shape? Do you agree with any points from my previous post?

(Don’t mind that you have only 2 decimal places precision in measurements, a small error is ok.)

1 Like

Hello- I do not see a good way to do this in Rhino just with the polyline command. The constraint system that is currently in the works should help when it is ready, but that is a big project.


From the user’s perspective, this is so simple, logical task to do… You don’t need a whole Parasolid kernel to draw lines like that. Please take a look at the video from Plasticity. It would help tremendously in drawing lines or drawing walls in Visual ARQ @fsalla . I just want to draw a line at an angle. I bet @Joshua_Kennedy could prepare such a drawing mode with ease.
And please remember, nobody will set the whole constraint system just to draw a couple of lines. I don’t have ambition to later edit these lines in parametric fashion, for starters it would be good just to draw them.

I have a VERY old .rvb script I wrote for someone back in 2009 - way before Python was integrated into Rhino and right at the beginning of my scripting experience. It’s pretty clutzy - there’s no preview, you just type distance and angle and then it adds next segment - but I think it does more or less what you want. If so, I can try to Pythonize it, and perhaps modernize it somewhat and make it a bit more interactive.

PolylineAngleLength.rvb (3.2 KB)

Thank you, I tested it. It’s close… angle calculation is made from the extension of the previous polyline, not quite what I expect, lack of preview of course can be frustrating at times and is unpleasant all the time. Generally, UX should be at least at the same level as in my video, but there is room to make it better.

You are clearly a “power user” but there should be some boundaries to where users like you should go, this seems so basic of a function that I am asking McNeel to properly implement it themselves.
Unfortunately, I’m not skilled enough to write a polyline drawing system for my 2023 CAD program.
I am not asking you to translate this system to Python, add a proper preview system, etc. If you will do it, it might help me in one job, but many other users will still not know about this function.
Thanks again Mitch, your effort is one more band-aid on a wounded Rhino body.

OK, from your video I thought that’s what you wanted, to be able to input angles relative to the previous segment.

There is the angle constraint at the command line. Line (place point) <30 will constrain the line to 30°, after which you can input a length and Enter for example… Those angles are absolute.

Whenever is possible to draw polylines this way in Rhino, you will be able to draw VisualARQ walls and other objects this way too.

that sounds way to cynical for me. also please reply directly to ones post if you want a response, i missed your comment from 1 1/2 years ago :man_shrugging:

the reason why such an awkward option did not surface in rhino is because nobody needed it. i personally never had to draw multiple lines (polylines whatever) in exact relative angles so plenty and so fast that i did not manage to construct these few with the normal lines command.

you still did not describe a real life user case… and if your entire world envelopes around having to draw in exact relative angles only then you are out of luck. sorry for the bad news.