Connect points and find the intersection between them

Hi all,

I am wondering if there is a grasshopper component that can find the intersection between the vantage point and the point on the building surface (Red circle).

In other words: find out which points on the building will be blocked by other buildings and cannot see the vantage point.

For example, the “blue line” will not be blocked by the geometry whereas the “orange line” may be blocked. I would like to find out which points on the building are able to see the vantage point and draw the “blue line”.

View and isovist analysis.3dm (156.5 KB)


not sure i understood, but maybe the command Bounce could help.

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you can “extrude all points” with the gumball - in any direction to get the red lines.
then turn on the control points of those lines and set the outer once
to your target point.
you get the blue lines…connecting your points with the target…
now use _intersect _trim or what ever fits to your needs…
another command that might help you is _extrudeCrvToPoint
kind regards

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I think I didn’t clarify the question well. As it will be much more points on the building, it seems that the command Bounce may not be the best tool.


Thanks @Tom_,

As there are much points than the test file, is it possible to do it in grasshopper?


Hello - this will get what I think you want in GH:

@hoganchan113 This might be better - no points from the back side of the target object:


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IVRay (IsoVist Ray) is what you want for this. (14.9 KB)

P.S. Hey, you already knew that from this thread you created back in October:



Hi @Joseph_Oster,

Yes. I did remember there is a GH component (Isovist ray in this case) that can create line between two points but I am not able to find it out. Thanks so much.