Hello all,
Just wondering if there is any way to edit the length of an existing curve? Also, when you pullback or project a curve onto a surface, does it change the length of the curve?
Thanks.
there are quite a few options doing that, you may have to state a more specific situation. starting with point editing a curve you can also trim a curve at anytime or use subcurve to shorten it along its own path. or use extend if you have a specific boundary. you also have ContinueCurve or ContinueInterpCrv if you want to proceed drawing a finished curve. it all depends what exactly you want.
actually pull and project change it
Command _squish and _squishback , tries to avoid this…with restrictions
Command _offsetCrvOnSrv can help sometimes…with restrictions
@Jaqomatic Do you want to trim a curve to a certain length, or do you want to resize a curve to a certain length, or something else?
Through some trial and error, I realized that project and pullback does change the dimensions of the curve. I’ll try out ContinueCurve command. I was just hoping there was a way to edit the length of an existing curve to a specific length. I’m realizing that the length changes when I do project/pullbacks and want to make it an exact length.
you still did not explain what exactly you need, is it an open curve or a closed one? on any curve SubCrv will do it along its own path, just select the curve enter the command select the start point and you can type the value of the total length into the value box and hit enter it will shorten it to the exact length.
extend will work similar just skip the boundaries if you dont have any, choose option natural on a curve it will proceed its curvature and click on the one end you want to extend, then enter the amount you want to add.
you can also use BoxEdit on closed curves if you want to have it confined but that will only stretch it orthogonal in the wished direction.
_Divide > option length> select direction> use split or mark the end
https://docs.mcneel.com/rhino/5/help/en-us/commands/divide.htm
2 Likes
Yes! Thank you Zsimon! This is EXACTLY what I needed. 
The command _SubCrv, along with the desired lenght can also be used.
psst, thats what i explained above already, but nobody seemed to have read it 
Hi RichardZ
It has been read but not understood. Often because of the language barrier happens. For this I have inserted a photo and a link.
Personally (custom only) use the _SubCrv command to shorten a curve without a specific measurement while using the _Divide command when I want to enter a specific measurement. The reason is simple, with the command _Divide setting the “length” option in the window appears the measurement of the selected curve, making it easier to get the desired result.
using SubCrv one can enter the exact length in the Value box.
result
divide can be used very similar, only the dim text field breaks…
at least in the latest whip
the effort seems the same in both commands.
Hi RichardZ
Still problems of understanding. With the _Divide command I can know the length of the source curve without doing anything. The value appears in the options window and I can set the desired value. With the _SubCrv command I have no way of knowing the length of the original curve. I add … that with the _SubCrv command I’m forced to measure the source curve (with an extra command). The problem with _SubCrv is when I want to shorten a curve and the desired value is greater than the length of the original curve.
-Simon
ahaaa 
you meant with the “specific length” the output length of the curve. sure thats handy if you need it. but i guess that when you use that command you already know that you have to shorten it to a specific length, entering an exact value in WYSIWYG manner will probably not be used very often 
but ok.
yes but divide does not help here either or does it for you? a command which would combine extend with shorten would be nice of course, but how often does one use exact lengths in shortening existing curves generally. if you have to do that often, then the approach of modelling probably has to be rethought entirely
permission denied?
Yeah, this is really stupid, I check “public view” as “permitted” and visibility to “All users” and it still doesn’t work.
It seems to be visible now…
probably because you are registered at youtrack?
YouTrack changed this behavior “for the weird” recently. You have to uncheck all the visibility boxes and then it sets the visibility to “All Users.” Said differently: “All Users” used to be an explicit option; now it’s implicit.
(This is still confusing people here at McNeel, and it’s been months)
1 Like