How to make a surface ends where it should?

Leonardo_G_Pate · September 30, 2020, 2:54am

Hi there, I made this surface but when I try to use it on grasshopper it behaves as if the surface is different. I need it to be one single surface

Anyone knows how to get around this?

surfacex.3dm (330.7 KB)

JP-Mike · September 30, 2020, 3:55am

I believe this surface made by using patch tool.

try to take the outlines make it 3 lines and add some sections like the picture below

then use sweep 2 tool . apply this tool to the curve No. 1 then 2 then 3 ten finish with the point . and you will have this result

surfacex.3dm (294.3 KB)

Leonardo_G_Pate · September 30, 2020, 5:12am

it needs to be a single surface, sorry didn’t said this.

JP-Mike · September 30, 2020, 6:19am

It’s already one surface ! ,

i believe it’s better to more clarify about what do you want

davidcockey · September 30, 2020, 9:19am

@Leonardo_G_Pate Your file contains a single trimmed surface and several curves.

wim · September 30, 2020, 9:56am

Hi Leonardo -

Many workflows in Grasshopper will take the underlaying untrimmed surface of your input.

That’s a frequently asked question.

-wim

Leonardo_G_Pate · September 30, 2020, 5:10pm

sorry, is because i really didn’t know how to call this situation and didin’t appeared any suggestions of simmilar content.

As a suggestion or (even a question maybe), it would be cool to have somewhere where people could see those FAQ of grasshopper and rhino. It would help me a lot.

Leonardo_G_Pate · September 30, 2020, 5:12pm

yeah, I don’t really know how to call it… Is a single surface, but its real boundaries are not being showed so whenever I am manipulating the surface, it uses the complete surface (the untrimmed one)

scottd · October 1, 2020, 2:40am

It is a trimmed surface. UV exists in the Untrimmed version of the surface and then there is a trim boundary on that surface that controls what is visible.

The challenge is that by splitting it by UV you get the untrimmed space. It is nicely organized because Untrimmed surfaces have only 4 sides. Here is an article on the organization: https://wiki.mcneel.com/rhino/nurbssurfaces

The trimmed version is more complicated. Because the trim curve can be any shape.

SO the trick that is covered in those threads is to get the untrimmed Grid, but then come back and test which points at off the surface and filter base don that. It also give the chance for Grasshopper to react to panels that span across the trim boundary.

As you can see there is a lot more consider when dealing with trims, but it is well worth the time to work thru it. By considering trims, there is a much larger set of geometry situations that can be handled.