Surface Orientation

I have been trying to write a definition for a class im taking on grasshopper, and have run into many issues. I ended up starting over and think i have isolated the issue. I have a Brep in rhino that I want to take into grasshopper to manipulate the edges. I explode the brep into planar surfaces and extract the edges (I have tried two different ways with the same results). just to illustrate the issue, i then recreate the planar surface from the edges, and bake it. The originating surface has all the surfaces oriented the same direction, but the final brep has some surfaces flipped. Im tyring to understand why this is happening and how to fix it. I have posted the rhino file, the definition, as well as a screenshot of the original brep vs the recreated one (Backfaces are pink)

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Permalink Reply by Ralf Lindemann on April 6, 2013 at 2:16pm

Ryan,

How do you create your surface? If it's with edgeSrf then that's probably the culprit. The component creates the surfaces a bit random. It's better to use sweep2. (I haven't got Rhino on the device I'm using right now so can't open your files)

Check the following link. There is a script you can use to flip surfaces around.

http://www.grasshopper3d.com/forum/topics/normals-errors-unify?comm...

Also the lunchBox Add-on created by Nathan Miller includes a component to flip surfaces.

Best,

Ralf

Permalink Reply by Ryan Grande on April 6, 2013 at 10:37pm

Yeah I did use edgeSrf, but i was hoping to figure out why it is creating the flipped surfaces. I later plug the surface edges into other definitions and all the same surfaces that are flipped cause other headaches. I was hoping to remedy the problem early on and avoid the issues this way, as opposed to correcting each issue as it arises But i could be wrong and the later issues have nothing to do with this one.

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