Trim surface with another surface

I'm always amazed how seemingly simple things turn into over-complicated if not impossible to do in grasshopper/rhino. I hope this is not another example.

Is there a way to trim a surface with another surface??

I'm just trying to do a simple embankment so I would like to trim the side surfaces with the terrain.

In the posted image I have a road and I created the lateral slopes (sweep) and now I would like to trim them with the terrain keeping only whats bellow that surface.

I've search everywhere but couldn't find what seams to be a very basic and useful operation. Is this possible?

Thanks

Attachments:

trim surfaces.jpg, 57 KB

Replies to This Discussion

Permalink Reply by Joseph Oster on November 21, 2017 at 6:48pm

You're likely to get better results if you post you GH model:

http://www.grasshopper3d.com/forum/topics/how-to-get-help-when-you-...

Don't know if this will help as it was a mesh, not a surface. Not necessarily simple!

http://www.grasshopper3d.com/forum/topics/volume-between-meshes?com...

Permalink Reply by Rui Fortes on November 22, 2017 at 7:48am

Here.

I want to trim the lateral surfaces (slopes?) that are above the terrain.

Seems simple but I just can't figure out how.

I attached the gh model also. (it only works with one road, going to make another post about that)

TIA

Attachments:

trim surface with surface.gh, 108 KB

Permalink Reply by Joseph Oster on November 22, 2017 at 8:50am

Permalink Reply by Rui Fortes on November 22, 2017 at 11:06am

Thanks a lot Joseph.

I didn't realize that if slope surface is big enough it would always split into a single surface to that side. duh :)

Permalink Reply by Joseph Oster on November 22, 2017 at 11:30am

It's not obvious from the screen shot (one of the drawbacks to not posting code), but the highlighted 'Shift List' component has the 'W (Wrap)' input set to false, so the first item in each list (the part you want to cut away) disappears.

By using 'SDiff' in the code I referred to yesterday, subtracting the solid roadway with side slopes from the solid terrain results in trimmed sides and "bottom" (the road itself), except for gaps between the road and low terrain areas that need to be filled in.

RSS