creating points on a surface of equal distance

Hello,

I would like to ask - if it is possible to create a gridshell in grasshopper so that all the elements would be of the same length.

I need to make a project and small physical model of such a gridshell made by balsa wood and I wonder if realisation of this can be simplified in some way - the only idea I have is to have equal length of the wooden elements.

I can imagine that it can be done on flat grid or , a cylinder (by a squared net, I suppose one sort of elements would be curved, and one sort would be straight) quite easily. How would it look like on hyperboloid, half of a sphere or on a half of ellipsoid?

I will be grateful for answer.

Iwona

Replies to This Discussion

Permalink Reply by Joanna on December 31, 2015 at 3:51am

hi!

Are you solved this problem?

Is it possible to build gridshell by the same elements?

Joanna

Permalink Reply by martyn hogg on December 31, 2015 at 5:28am

Have a look at geodesic domes. These are derived from an icosohedron which is a 20 sided shape made up from equilateral triangles. In this case all the nodes are equidistant. As you add more divisions to the triangles they become slightly less equilateral.

There have been some discussions on here about structures with fixed length equal struts but I'm on my phone at the moment and can't post the links.

If you constrain the nodes to be equidistant the surfaces you can make become irregular and quite kinked. I think Daniel Piker posted an interesting Kangaroo definition that simulated this.

In summary, structures with curvature in one direction can be done fairly easily with equidistant nodes but it gets complicated for structures with curvature in more than one direction.

If I can get on my laptop later I will look up the links to similar discussions.

Permalink Reply by Laurent DELRIEU on December 31, 2015 at 6:13am

There is a tool for approximating a shape with some struts and just one type of node.

http://www.graphics.rwth-aachen.de/software/zometool

Permalink Reply by Joanna on December 31, 2015 at 7:38am

Laurent, it looks great. thanks! I would like to do a similar script in GH.
im interesting in: I want to know what determines the possibility of building structure of preset items.

I don`t know.... maybe it`s impossible... hmmmmmm :)

Permalink Reply by Joanna on December 31, 2015 at 6:17am

thanks!

structures with curvature in more than one direction are the most interesting. and
determine the extent of the length of elements. I will ge grateful for the link :)

Permalink Reply by martyn hogg on January 2, 2016 at 3:17am

Here's a good discussion...

http://www.grasshopper3d.com/forum/topics/polygon-composition-with-...

I was convinced you couldn't have curvature in 2 directions until Daniel proved me wrong. There is a Kangaroo definition that lets you explore what sort of surfaces you can get.

However matching a surface with a gridshell constrained to equal strut lengths will be tricky!

Permalink Reply by Joanna on January 2, 2016 at 10:25am

thanks. it`s heplful. but what do you think - is it possible to build a structure with more control? e.g. defining points or edges? or giving three different length...? I`m not the best in GH...

I'm trying to get a geometry as on foto. Moving points are not very accurate. Do you have any idea?

Permalink Reply by martyn hogg on January 2, 2016 at 4:40pm

Well you can create something like that defined from the 4 corner points...

I'm not sure how you would then constrain the structure to only using 3 lengths of struts.

You can use Kangaroo to do this sort of thing I think - i.e. try to equalise the strut lengths, but I can't help you with that... it's beyond me!

Look at the definition... at the end I work out the lengths of the edges, sort them and group them so you can see the lengths. There are lots of similar lengths but they are all slightly different.

In practice, if you were going to construct this, the nodes could be designed to accomodate small variations in strut length so you could rationalise struts within a certain range. For example, the nodes could have a threaded bar sticking out for each strut and this thread would allow for a range of strut length.

Peter F is the man for this kind of thing.

Attachments:

GridshellEx.gh, 11 KB

Permalink Reply by Joanna on January 7, 2016 at 11:11am

hi!

thanks for your example.

Please, look at my files. What do you think about this? This script is looking for a situation where the length of the elements are most similar to each other. I hope so :)

But I have a problem with:

1. how to add numbers of elements? (i dont know which elem. have length from list)
2. how to arrange long ascending ?

3. how to eliminated the elements on the edge from calculations? (because I want to analyze only elements forming a grid)

Attachments: