How to set limitation?

Hi. I am fairly new to Grasshopper and I am trying to do something using Grasshopper with a Patch surface I did in Rhino. Can I set a limitation to prevent Area detact the central points of the “Invisible Surface” ?

Patch.3dm (200.0 KB)

Central (7.4 KB)

When I click on the link for Patch.3dm, I get this error message:

Oops! That page doesn’t exist or is private.

I created a patch surface and internalized it in this GH file: (20.9 KB)

Flatten and Graft have no effect at all here so I disabled them.

Sorry, it might be because of I am using the file while uploading it. Can you try it again? Thank you.

Yep, it works now. This version uses your surface - again, internalized in this GH file: (76.9 KB)

Thank you Joseph!

One more question. May I know how did you get the figure 0.034 in the Smaller Than command?

Arbitrary. Move the slider and see what happens. The Pull ‘D’ (Distance) for points within the perimeter of the surface should be zero, while all the points outside the surface will have a greater distance value. But in fact, the “good ones” don’t equal zero exactly so testing for a “less than” value that’s close to zero gets the job done. In fact, as you can see, the distance for most of the points outside of the surface is greater than one.


You have been a great help, thank you very much!