Newbie question: Boundary surfaces error

Hi there,

I am new to grasshopper as I am learning it as part of my architecture degree at university, so my question probably has an obvious answer.

I have been having several issues tying to make a model for a project using rhino and grasshopper. My intention was to make a quick and sketchy 3d model which I would later 3d print to show my ideas - but it hasn't been as simple as I intended.

I created several nurbs curves and polylines using grasshopper to make an outline for the surface I wanted to create. Then I Joined the curves and plugged the result into Boundary surface, which gave me an error "planar surface routine returned no result"

I was up for several hours last night trying to find out why this wasn't working and tried many other ways to create this surface. The other way I tried was to bake the joined curve into rhino, explode, loft the two curves opposite one another, then merge all the surfaces - this gave me the surface I wanted, but then when I plugged this surface back into grasshopper the result was all squared off and not rounded like I desired.

If I could get some easy answers to my problem I would be more than grateful - Like I said, I am new to this software so go easy on me

Replies to This Discussion

Permalink Reply by ng5 Alex on March 23, 2017 at 5:05am

Hello Alex,

it is suggested to post the rhino and grasshopper file when posting a question.

Boundary surface component works with planar curves. If your curves are planar, it will not output any surface. There is a planar component to check if your joined curves are planar, in case they aren't obviously planar through visual inspection.

For the second part, if the loft worked for you in Rhino, why don't you loft them inside grasshopper?

best

alex

Permalink Reply by Joseph Oster on March 23, 2017 at 7:02am

I thin k you meant to say "If your curves are NOT planar, it will not output any surface."?

And yeah, posting GH code and/or a Rhino file helps immensely!

Read this first! How to get help on this forum. http://www.grasshopper3d.com/forum/categories/discussion-1/listForC...

Permalink Reply by ng5 Alex on March 23, 2017 at 7:15am

ah yes, no curve planarity ---> no surface from boundary surface component.

Permalink Reply by Joseph Oster on March 23, 2017 at 8:38am

This example is a little silly... It demonstrates joining three curves (nurbs, arc and polyline) to form a boundary surface. I started to say this but the example proves me wrong:

Sometimes you have to flatten the input to curve 'Join' to get a single curve result. In any case, seeing "Closed Planar Curve" before 'Boundary' is CRUCIAL to success.

I'll just say that I've seen examples where it was true. ;) Post your curves!

Attachments:

boundary_2017Mar23a.gh, 27 KB

Permalink Reply by alex morgan on March 23, 2017 at 9:47am

Wow, I wasn't expecting responses so quickly, Thanks to every ones reply.

I have attached my grasshopper file below- It's a bit of a mess so apologies for that.
I have tried the tips suggested but still cannot seem to get it to work.
I have spent hours today trying various other methods - but when I test trying to import it into revit as a .sat file, it loses some of the surfaces. I think the whole issue stems from my dodgy grasshopper work in the beginning.

If you wouldn't mind taking a look at my file, that would be great :)

Attachments:

Boundary surface problem.gh, 27 KB

Permalink Reply by Joseph Oster on March 23, 2017 at 10:25am

I don't have the "Grevit Revit Wall" plugin... But I can see your code anyway. OMG! That's quite a mess of code, indeed. I hardly know where to begin.

Do you understand what a "planar curve" is? It means the entire curve is in a single plane, effectively flat. What you have is nothing like that. There are parts of your geometry that appear to be planar, if only you were more selective about your curve joins.

Here is something... None of these surfaces are 'Boundary', though some could be if the edge curves were different. This is not a great way to get things done (manually setting a bunch of points and selecting sets of them to make nurbs and polyline curves. If you must, then choose your curves more carefully. I urge you to re-examine your whole approach to this.

And please remember that without posting your GH file, there is no way to help you on a problem like this.

P.S. Not shown in the image but added to the code, there is a 'Brep Join' off to the right that joins these six surfaces I created into a single "Open Brep" surface.

Attachments: