Subsurface is invalid because the trimming V-domain is singular

Hi everyone, I'm having a problem with my understanding of domains:
I'm trying to divide a square surface into 9 subsurfaces (3x3), and keeping only the subsurfaces that are in the corners (see image attached). I got it working in a separate definition, but when I add this to an existing definition, I get the error: "Subsurface is invalid because the trimming V-domain is singular."

Q: How can I fix this?
And how come the U-domain doesn't result in a "singular domain"-error? It's the same as the V-domain.
Can someone please explain?

Attachments:

singular V-domain.png, 103 KB

Replies to This Discussion

Permalink Reply by David Rutten on March 13, 2011 at 9:37am

Hi Pieter,

when you trim a surface, the trimming domain is intersected with the actual surface domain. So if the surface domain is smaller than your trimming domain, you might end up with a trimming domain that has no width (or height).

You'll either need to measure the actual surface domain and create your corner trims based on that, or you need to Reparameterize the surface domain in which case you know for sure it is always 0~1 in both directions.

David Rutten

david@mcneel.com

Poprad, Slovakia

Permalink Reply by Pieter Segeren on March 13, 2011 at 10:41am

Thanks David, it was a problem with my measurement of the original surface. So I chose your second approach: remapping and reparameterizing, than it worked :) Dankjewel!

Permalink Reply by L]G on February 2, 2013 at 8:13pm

I have the same problem as Pierter, i was following a tutorial and i am stuck. i need to trim a number of surfaces to get the desired lofted objects. the tutorial has been done using an earlier version of grasshopper and sometimes it does not match. thanks and i hope you guys can help

Attachments:

Permalink Reply by L]G on February 2, 2013 at 8:14pm

i have tried parameterizing and grafting and everyother combo and i can get the desired effect. thanks again

Permalink Reply by Pieter Segeren on February 3, 2013 at 12:40pm

Hi L]G, I'm missing the geometry which makes it really hard to say anything useful about the definition. Can you reupload your definition with the referenced geometry internalised, or upload the rhino file please?

Or did you just say you fixed it already: "and i can get the desired effect" ..?

Permalink Reply by L]G on February 3, 2013 at 12:49pm

Hi, sorry i meant i can't get the effect. here is the rhino file and the ghx. thanks

Attachments:

singular v and u.gh, 52 KB
planar evolution_gh.3dm, 141 KB

Permalink Reply by L]G on February 3, 2013 at 12:53pm

i check which of the lofted surfaces needed to be culled and it doesnt follow any patterns. using an item list, the surfaces that i want to get rid of are 4,9,14,31,32,46,47,48,61,62,63 out of 76 surfaces. cheers

Permalink Reply by Pieter Segeren on February 3, 2013 at 4:00pm

Ah, I guess the Domain(s) you are creating are incorrect. Check the U-input of the Create Domain component. This should be like : 0 To 0.33 , 0.33 To 0.67 , 0.67 To 1 , try the Consecutive Domains component.

Attachments:

Domains.png, 58 KB

Permalink Reply by L]G on February 4, 2013 at 12:36am

hi pieter, thanks that works in terms of the isotrim component but the end result is very different to the effect i am after. attached are a photo of how the rhino looks, and another one of the desired effect. in the second photo are highlighted in yellow the surfaces i am trying to cull. i dont mind doing it manually after baking but i was hoping there was a way. thanks

Attachments:

domain component.png, 253 KB
domain component_1.png, 289 KB

Permalink Reply by Pieter Segeren on February 4, 2013 at 10:15am

To be honest I still don't get what effect you are after L]G, I'm sorry.
If you were to cull one file manually, or make a sketch of it, I might see what you mean, and be able to say something helpfull...

Permalink Reply by L]G on February 4, 2013 at 10:28am

hi pieter, i am trying to get the surfaces to loft as in photo 2, but i can only get it to loft as in photo 1. i dont know how to cull the extra lofting. attached is the ghx with the changes you suggested. sorry if im being comfusing and thanks for the help

cheers

lucas

Attachments:

1.png, 267 KB
2.png, 268 KB
ribbed connection nodes_1.gh, 55 KB

Permalink Reply by Hannes Löschke on February 4, 2013 at 12:48pm

Your Problem is lofting all sections in one single loft. This results in connections between the single original box geometries.

Flattening in a multiple object situation will destroy any grouping. It's quite frustrating. ShiftPath will flatten the last branching level while keeping separate paths for each base object.

Attachments: