Grasshopper calculations

So I'm trying to figure this out in grasshopper and am having a little trouble. I have 2 surfaces on different planes. I subdivided each surface and connected the X's with lines to see where they intersect.

There are a few buildings (or polysurfaces) that "block" these intersecting lines. I'm trying to figure out if there is a way in grasshopper to calculate how much of the intersecting lines are being blocked by other surfaces. I attached the rhino file with the grasshopper file if that helps.

Attachments:

GRASSHOPPER INTERSECTING LINES.png, 134 KB

Replies to This Discussion

Permalink Reply by ng5 Alex on September 28, 2014 at 9:05am

Hello

something must have gone wrong . there are no rhino or grasshopper files uploaded.

please post them to check it out.

cheers

alex

Permalink Reply by Norm Sash on September 28, 2014 at 10:18am

Maybe use an isovist component to detect the object collision and then subtract the resultant collision length from the line length? I think that would give you the amount of your lines that is obstructed by the object.

Permalink Reply by An on September 28, 2014 at 10:32am

You can use "Dispatch" to see which lines are colliding with another object. Dispatch essentially allows you to filter streams based on True/False conditions. So you would just set the lines to intersect the objects, use the "Larger than" operator to filter intersections that are above 0 intersections and get true/false outputs, and use that list of true/false in dispatch to divide the set of lines into those that have 0 intersections and those that have more than 0 intersections.

EDIT: I don't see a way to attach a gh file as a reply so I'm linking an image of what that setup looks like - http://i.imgur.com/5MOP9O8.png On the left, the BRep is the object that's colliding, and the Crv is the set of lines you want to check.

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