Sweep 2 Problem

Sweep 2 Problem:

I have attached a Grasshopper definition, a Rhino file and a screen-shot of the problem area. Essentially I have a set of curves constructed from points. In one instance I was able to use the Swp2 button to successfully sweep between 2 rail curves using 1 section curve. In the other instance with the same section curve and 2 different rail curves, the Swp2 button does not produce a surface, (as you can see the button also does not show signs of error). Have I hit a bug, have I missed some crucial step or piece of input?
Any help appreciated.
Thanks, Eli

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Replies to This Discussion

Permalink Reply by diego on July 21, 2009 at 8:09am

try inverting your connections, connect the item as r1, the bzspan as r2, and the curve on the S input, and flatten the item, it worked when i tried it,

diego

Attachments:

unit_construction.ghx, 886 KB

Permalink Reply by Eli Allen on July 21, 2009 at 8:19am

Diego,

Thanks for the feedback, of course it worked. I had been trying to work around this for two frustrating days and somehow never hit on that particular switch.

Best, Eli

Permalink Reply by Paxton Sheldahl on October 19, 2009 at 4:14pm

I also had this issue..another step that came up was the order and first point which the curves were made. If they are not aligned, the sweep2 component will turn grey with no errors...but no output either.

Just add the flip component to one of your rails and it will resolve.

just another thing that may go wrong with the sweep2 command.

Paxton

Permalink Reply by Roberto Maffei on October 27, 2010 at 10:04am

dear,

i still have the same problem.
No sweep surface.

can you hel me with this? I've attached the files

Thanks a lot

roberto

Attachments:

sweep2 error.3dm, 28 KB
sweep2.ghx, 25 KB

Permalink Reply by Eli Allen on October 27, 2010 at 3:47pm

Roberto,
It seems that the sweep curve must be located at the starting points of your rail curves. The solution for this is simply to select borth rail curves in your Rhino window and type the command "flip." Alternatively you could use a flip button in Grasshopper, but for something this simple it doesn't seem needed. I have uploaded a corrected Rhino file that should work with the grasshopper script you had.
Best, Eli

Attachments:

sweep2error_EKA_FIXED.3dm, 52 KB

Permalink Reply by Roberto Maffei on October 27, 2010 at 3:56pm

great, thanks a lot!

but can you tell me how can i understand what's the direction of my curve? because this file was a simplification but i have a much complex file in grasshopper and the lines derives from other commands...

Thanks

Robi

Permalink Reply by Eli Allen on October 27, 2010 at 4:18pm

In Rhino, if you have a curve, you type the command "Dir" to display the curve normals, which will tell you the direction. I'm not really sure that there is a similar command in Grasshopper. However the curve direction will generally go from the start point of the curve to the end point of the curve. There are would be a number of ways to visualize this vector by building a small definition, take a look at the attached files to see an example that might help. Notice that the second set shows the effect of the "Flip" button, which can be used to flip curves that are not going the direction you would like.

Eli

Attachments:

CurveDirectionVisualization.ghx, 123 KB
CurveDirectionVisualization.3dm, 59 KB

Permalink Reply by Roberto Maffei on October 28, 2010 at 1:59am

thanks eli

it seems the direction is ok but still sweep 2 doesn't work in grasshopper even if it works in rhino (flipping the direction, as you did).

here is my file.
i tried to isolate the command sweep 2 in the bottom-right side of the gh file.

Thanks for you help

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