# "Sweep 2 Rails" gets two hits in two different files

**URL:** <https://discourse.mcneel.com/t/sweep-2-rails-gets-two-hits-in-two-different-files/10152>\
**Category:** Rhino for Mac\
**Created:** [July 21, 2014, 6:21pm UTC](https://discourse.mcneel.com/t/sweep-2-rails-gets-two-hits-in-two-different-files/10152 "2014-07-21T18:21:56Z")\
**Posts on this page:** 13\
**Page:** 1

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**Author:** ![Giuseppe\_Zimbone](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/giuseppe_zimbone/32/43386_2.png) [@Giuseppe\_Zimbone](https://discourse.mcneel.com/u/Giuseppe_Zimbone)\
**Post date:** [July 21, 2014, 6:21pm UTC](https://discourse.mcneel.com/t/sweep-2-rails-gets-two-hits-in-two-different-files/10152/1 "2014-07-21T18:21:56Z")

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![](https://sea3.discourse-cdn.com/mcneel/uploads/default/10928/11598c09618ccb21.jpg)  
 ![](https://sea3.discourse-cdn.com/mcneel/uploads/default/10929/eb6ce20fea294d89.jpg)

The first object is a piece of a boat that I’m drawing, done with the command “sweeo 2 rails.” This surface is not continuous, it has a cut on the curve. I have tried all the possible variations in executing the command, but the result is always the same  
The object “edge cockpit” is obtained by copying the two rails and the two sections and pasting them into a new file. This surface has no discontinuities instead.  
I do not understand the difference in the outcome.

Software information

Software versions  
Rhinoceros version: 5.0 Wenatchee 2014-07-14 (518)  
OS X version: Versione 10.9.4 (Build 13E28)

Plug-ins  
None

Hardware information

Computer hardware  
Hardware model: MacBookPro6,1  
Processor: Intel Core i5 CPU M 540 @ 2.53GHz  
Memory: 4 GB  
Architecture: Intel 64 bit

Video hardware  
Graphics: NVIDIA GeForce GT 330M 512 MB  
Memory: 512 MB  
Screen size: 1920 x 1200  
Displays: LCD colori

Third party kernel extensions  
com.sophos.nke.swi (9.0.53)  
com.sophos.kext.sav (9.0.61)

USB devices  
Apple Inc.: Apple Internal Keyboard / Trackpad  
Apple Inc.: Bluetooth USB Host Controller  
Primax Electronics: Apple Optical USB Mouse  
Apple Computer, Inc.: IR Receiver  
Apple Inc.: Built-in iSight

Bluetooth devices  
None

OpenGL information

OpenGL software  
OpenGL version: 2.1 NVIDIA-8.24.15 310.90.9.05f01  
Render version: 2.1  
Shading language: 1.20  
Maximum texture size: 8192 x 8192  
Z-buffer depth: 24 bits  
Maximum viewport size: 8192 x 8192

Implementation settings  
Use texture compression: No

Appearance settings  
Antialiasing: 4x  
Mip map filtering: Nessuno  
Anisotropic filtering: Nessuno

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<div class="post-metadata">

**Author:** ![John\_Brock](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/john_brock/32/476283_2.png) [@John\_Brock](https://discourse.mcneel.com/u/John_Brock)\
**Post date:** [July 21, 2014, 9:24pm UTC](https://discourse.mcneel.com/t/sweep-2-rails-gets-two-hits-in-two-different-files/10152/2 "2014-07-21T21:24:04Z")

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It looks like your rail curves aren’t smooth. They appear to have kinks in them so Rhino is doing the best it can with poor input curves.

Can you please attach a 3dm file with the curves you’re using so we can have a look?

Thanks

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**Author:** ![Giuseppe\_Zimbone](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/giuseppe_zimbone/32/43386_2.png) [@Giuseppe\_Zimbone](https://discourse.mcneel.com/u/Giuseppe_Zimbone)\
**Post date:** [July 22, 2014, 9:09am UTC](https://discourse.mcneel.com/t/sweep-2-rails-gets-two-hits-in-two-different-files/10152/3 "2014-07-22T09:09:35Z")

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Hello John,  
do not laugh at my project, I try to draw a boat for hobby; I normally design houses with Archicad.  
Thanks  
[BARCA5.3dm](https://sea3.discourse-cdn.com/mcneel/uploads/default/10937/f2f9b87a76536edf.3dm) (4.2 MB)

[bordo pozzetto.3dm](https://sea3.discourse-cdn.com/mcneel/uploads/default/10938/a2ae75edfc8fe6c9.3dm) (2.65 MB)

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**Author:** ![pascal](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/pascal/32/479395_2.png) [@pascal](https://discourse.mcneel.com/u/pascal)\
**Post date:** [July 22, 2014, 3:41pm UTC](https://discourse.mcneel.com/t/sweep-2-rails-gets-two-hits-in-two-different-files/10152/4 "2014-07-22T15:41:23Z")

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Hi Giuseppe- with this set-up, I’d use the ‘Add slash’ function as in the attached file to force the sweep to line up to the corner curves. You could also do it in three parts, also included.

[bordo pozzetto\_PG.3dm](https://sea3.discourse-cdn.com/mcneel/uploads/default/10947/b92defe53e944225.3dm) (2.2 MB)

-Pascal

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<div class="post-metadata">

**Author:** ![John\_Brock](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/john_brock/32/476283_2.png) [@John\_Brock](https://discourse.mcneel.com/u/John_Brock)\
**Post date:** [July 22, 2014, 4:16pm UTC](https://discourse.mcneel.com/t/sweep-2-rails-gets-two-hits-in-two-different-files/10152/5 "2014-07-22T16:16:21Z")

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Hi  
The first thing I noticed when I inspected your curves, is they don’t have the same number of control points distributed the same way to define the same feature. Turn on control points (F10) to see them. The two profile curves look pretty good. The one on the right (positive X direction) is perfect. The left one just has a few extra points. Since the rail curves have a simpler shape then the profile curves, they should have less points.  
Here are the points on your curves:  
 ![](https://sea3.discourse-cdn.com/mcneel/uploads/default/10946/102b1dab1dac401a.png)

Here are the curves after I cleaned them up and made the points match better:  
 ![](https://sea3.discourse-cdn.com/mcneel/uploads/default/10953/a97b7e3053d53f17.png)

I did three sweeps instead of 1 to get cleaner surfaces:  
 ![](https://sea3.discourse-cdn.com/mcneel/uploads/default/10954/f84af36b86dc2495.png)

Here’s a shaded view:  
 ![](https://sea3.discourse-cdn.com/mcneel/uploads/default/10955/552e0b1552f2fabc.png)

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<div class="post-metadata">

**Author:** ![Giuseppe\_Zimbone](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/giuseppe_zimbone/32/43386_2.png) [@Giuseppe\_Zimbone](https://discourse.mcneel.com/u/Giuseppe_Zimbone)\
**Post date:** [July 22, 2014, 4:49pm UTC](https://discourse.mcneel.com/t/sweep-2-rails-gets-two-hits-in-two-different-files/10152/6 "2014-07-22T16:49:32Z")

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Thanks John,

I learned a new thing.  
Is there a command to clean the curves or you must do that by hand?

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<div class="post-metadata">

**Author:** ![John\_Brock](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/john_brock/32/476283_2.png) [@John\_Brock](https://discourse.mcneel.com/u/John_Brock)\
**Post date:** [July 22, 2014, 5:00pm UTC](https://discourse.mcneel.com/t/sweep-2-rails-gets-two-hits-in-two-different-files/10152/7 "2014-07-22T17:00:05Z")

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There are a variety of commands. In this case I used Rebuild, RebuildNonUniform, Split and I manually deleted a few points too. There is no magic “CleanUpMyCurvesSoThisWillWorkBetter” command unfortunately.

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<div class="post-metadata">

**Author:** ![Giuseppe\_Zimbone](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/giuseppe_zimbone/32/43386_2.png) [@Giuseppe\_Zimbone](https://discourse.mcneel.com/u/Giuseppe_Zimbone)\
**Post date:** [July 22, 2014, 5:19pm UTC](https://discourse.mcneel.com/t/sweep-2-rails-gets-two-hits-in-two-different-files/10152/8 "2014-07-22T17:19:22Z")

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Ok John,

helpful and pleasant.

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<div class="post-metadata">

**Author:** ![Giuseppe\_Zimbone](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/giuseppe_zimbone/32/43386_2.png) [@Giuseppe\_Zimbone](https://discourse.mcneel.com/u/Giuseppe_Zimbone)\
**Post date:** [July 24, 2014, 3:06pm UTC](https://discourse.mcneel.com/t/sweep-2-rails-gets-two-hits-in-two-different-files/10152/9 "2014-07-24T15:06:33Z")

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I thought I had figured out how it works, I have redrawn the lines and curves so that they are as simple as possible and I checked that had the same control points distributed in the same proportions; but the result is worse than before.  
Where am I wrong?………  
[prova sweep2.3dm](https://sea3.discourse-cdn.com/mcneel/uploads/default/11009/a639f3d56b911fa8.3dm) (2.15 MB)

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<div class="post-metadata">

**Author:** ![Giuseppe\_Zimbone](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/giuseppe_zimbone/32/43386_2.png) [@Giuseppe\_Zimbone](https://discourse.mcneel.com/u/Giuseppe_Zimbone)\
**Post date:** [July 24, 2014, 4:11pm UTC](https://discourse.mcneel.com/t/sweep-2-rails-gets-two-hits-in-two-different-files/10152/10 "2014-07-24T16:11:34Z")

</div>

I thought I had figured out how it works, I have redrawn the lines and curves so that they are as simple as possible and I checked that had the same control points distributed in the same proportions; but the result is worse than before.  
Where am I wrong?………  
[prova sweep2.3dm](https://sea3.discourse-cdn.com/mcneel/uploads/default/11009/a639f3d56b911fa8.3dm) (2.15 MB)

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<div class="post-metadata">

**Author:** ![pascal](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/pascal/32/479395_2.png) [@pascal](https://discourse.mcneel.com/u/pascal)\
**Post date:** [July 24, 2014, 4:32pm UTC](https://discourse.mcneel.com/t/sweep-2-rails-gets-two-hits-in-two-different-files/10152/11 "2014-07-24T16:32:25Z")

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Hi Giuseppe- just in case - did you see the file attached to my post above? I think the simple way out is to use ‘Add Slash’ in Sweep2. You might want to SimplifyCrv the rails beforehand as well.

-Pascal

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<div class="post-metadata">

**Author:** ![John\_Brock](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/john_brock/32/476283_2.png) [@John\_Brock](https://discourse.mcneel.com/u/John_Brock)\
**Post date:** [July 25, 2014, 1:53am UTC](https://discourse.mcneel.com/t/sweep-2-rails-gets-two-hits-in-two-different-files/10152/12 "2014-07-25T01:53:48Z")

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Pascal is right, this is what Add slash is for. I used the older, less elegant technique of doing three separate sweeps and Joining them

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<div class="post-metadata">

**Author:** ![Giuseppe\_Zimbone](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/giuseppe_zimbone/32/43386_2.png) [@Giuseppe\_Zimbone](https://discourse.mcneel.com/u/Giuseppe_Zimbone)\
**Post date:** [July 26, 2014, 12:29pm UTC](https://discourse.mcneel.com/t/sweep-2-rails-gets-two-hits-in-two-different-files/10152/13 "2014-07-26T12:29:59Z")

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Hi Pascal, Hi John,  
Sorry for my English which is by google-translate.  
I use Rhino Italian and I think “insert Slash” is the same command: Edit\> Control Points\> Insert point of discontinuity. "  
I have seen the file “pozzetto\_PG.3dm edge”, but the result is the same as mine “bordo\_pozzetto.3dm”, where I had not entered “slash”.  
I tried to insert points of discontinuity in the file “BARCA5.3dm”, but the result is still wrong.  
I remind you that my question was, why did the same curves with the same command in the file “BARCA5.3dm” give a wrong result, while in the file “bordo\_pozzetto.3dm” give a correct result?  
The first is the entire project, the second has only the lines concerned.  
However, following the advice of John, by running the command three times, I get a good result also apparent in the file “BARCA5.3dm,” although do not know how to interpret the analysis of the zebras.

Thank you for your patience and availability.  
 ![](https://sea3.discourse-cdn.com/mcneel/uploads/default/11057/c850444023779c72.png)