Trimming Multiple Objects

So I'm wondering if the following is even possible:

I'm trying to split a list of curves or surfaces in grasshopper by having the largest shape become the trimming object in each trimming scenario.

Any help would be great thanks guys!

Replies to This Discussion

Permalink Reply by Justin on June 22, 2016 at 1:48pm

I guess I'd like a grasshopper approach to the "curveboolean" command in rhino...

Permalink Reply by Ethan Gross on June 22, 2016 at 2:05pm

Have you tried Region Difference under Intersection-> Shape?

Permalink Reply by Justin on June 22, 2016 at 2:07pm

Hi Ethan,

Thanks for the response, I am aware of those intersection components. I guess my real problem here was coming up with a clever way to solve multiple intersections at once... Any ideas?

Permalink Reply by Christian Gartland on June 22, 2016 at 2:19pm

Here's a start...but it's hard to determine exactly how to do this with grasshopper if there's no clear hierarchy to the group of squares. I think it might be better to just use the curve boolean command in Rhino.

The quick definition I made separates a list of rectangles into two halves--small and large, but doesn't address the issue of establishing a more local hierarchy. In other words, you might have a group of rectangles which falls completely into the list of smaller rectangles (since it samples the entire population), but none of them would be trimmed with each other.

Attachments:

region difference.gh, 9 KB

Permalink Reply by Justin on June 22, 2016 at 2:33pm

Hi Christian,

Thank you as well for the quick response. Like I mentioned to Ethan and you mentioned in your response, the real problem here is creating that hierarchy, and I'm beginning to think this is a much more loaded question than I had hoped for...

Let me know if you have any other ideas and thanks again for the work!

Permalink Reply by Mohamed Naeim on June 22, 2016 at 4:10pm

in my opinion, it should be simple

by sorting according to area, you extrude according to new order

then you use rhino command make 2d

done below

Permalink Reply by Mohamed Naeim on June 22, 2016 at 4:12pm

Permalink Reply by Ethan Gross on June 22, 2016 at 4:34pm

Clever! I guess you're assuming the extruded heights vary like the the area.

Permalink Reply by Mohamed Naeim on June 22, 2016 at 5:33pm

exactly sort surfaces according to area, then extrude according to index value

when use make2D command, make sure not to draw hidden lines(settiings)

Permalink Reply by Justin on June 23, 2016 at 7:05am

hmmm that is a pretty clever approach Mohamed. I was trying to stay completely in grasshopper, so maybe there's a different way to get this new line work other than using Rhino's Make2d... I'm going to give this a try and let you know what I come up with.

Thanks again for the help!

Permalink Reply by mire on June 23, 2016 at 7:51am

You might not need Make2d, after the extrusion you can:

_solid union the boxes

_extract from the joined brep only the faces with a z normal (assuming you are drawing in XY plane)

_extract the edges of the faces and project back to XY

Should work right?

Permalink Reply by Justin on June 23, 2016 at 8:28am

Hi Mire,

This definitely sounds like it could work, I'm running into some trouble with the solid union component working with multiple objects but I should be able to work around it.

I will let you know how it goes, thanks again guys!