How can I remove a specific part of a brep?

Apologies for the vague title. I’m not too sure how best to word my question.

I’m a student who is new to grasshopper and I have been set coursework to model a structure. I have decided to create a model based on London King’s Cross Station. I am currently trying to model the parametric design that sits inside the station.

For context, the structure looks like this:

Currently, my model of the structure looks like this:

I want to get rid of this part of the model:

And keep parts of the brep that is inside the train station exterior (lofted surface)

I’ve highlighted the brep and the lofted surface in my grasshopper file (again, sorry for the mess. I’m really bad and new to grasshopper):

coursework (81.3 KB)

Any help would be much appreciated, thank you.

check this post:

first of all it is not a grasshopper problem but you are facing:

  • a self intersecting surface
  • a far from orgin issue

don t expect that other s work through a defintion like this:

Dependend on several plug-ins.

first step:
bake the geometry and find the rhino-modelling workflow, to achieve what you want.
then transfer this manual workflow to gh.

Here’s one possible approach to re-model the loft surface from your file (simpler than trying to fix what you have). (14.9 KB)

Same technique could be used to replace the other loft surface as well.

Your file contains 4 python scripts that could be easily be replaced with native components. :question:


@Tom_P ditto

@Jenna2 you need to reconstruct that loft. i’m sure that messy shape is not what you intended.
can you sketch how it’s supposed to look like?

Hi Kevin,

Thank you so much for this grasshopper file!!! This is the shape I was trying to model but failed absolutely horribly to achieve.