membrane structure - beginning

Hello everyone,

I have an idea for a project of membrane structure, unfortunately i don't know how to begin and i ask you for help.

First of all my topic membrane structure built on four arcs (truss)

In the middle I plan to make a "hole" which would go almost to the ground (it is connected with the location of the project - underneath there is a tiny, currently dry pond, so the water from the "roof" would go there). Photo below - on the right side you can see sort of funnel going to the ground (opposed to one going up ;)) - thats exactly what i would like to achieve.

Below i post a screenshot from Rhino - I hope it more or less explains the idea - black lines are boundaries, purple ones are drawn to show what i imagine the surface would (more or less) look like.

I'm still on the beginning of my adventure with Rhino/GH and have never done such project. I've done some research on membranes and i found a lot of information about forming these like soap bubbles (perfect shape is a minimal structure in a given boundary) - here i ask you for help. I know about RhinoMembrane plugin. I watched tutorials on YT and have been experimenting to get the result that i wanted but with no succes (I used it inside Rhino so far, didn't use GH components).

I'm completely lost and have no idea what my next step should be - i dont even know how to prepare a mesh for this one - I hope you could help me a bit - how should i begin, is it possible to achieve such results with Rhino Membrane or should i approach the problem diffrently? Maybe Kangaroo? (if so please give me few tips - I only used it twice so far). I'll be grateful for any information or help.

Pardon my english,

Thank you for your time and enjoy your weekend :).

Replies to This Discussion

Permalink Reply by Ryan Whitby on October 23, 2014 at 6:21pm

Kangaroo would definitely be the way I would approach this project. If you download the example files here and look in the tensile category you will find some information that would be very relevant.

Permalink Reply by peter fotiadis on October 24, 2014 at 12:01am

Well, this is rather easy:

1. See this http://www.grasshopper3d.com/forum/topics/tensile-membranes-test3

2. The v5 version (l'll post the def in a few days) does everything that you want "automatically"

2. In case that you are lost (not unlikely) here's a generic guideline with the above def in mind:

2.1. Get the gist of the separation "techniques" as regards peripheral edges (as we do in real-life), cables from anchor points to membrane anchor plates blah, blah, blah. Decide your anchor policy (what is fixed and why) as well.

2.1. Patch the boundary curves and the circle (that does the C#) and then make a hole (or more) since patch doesn't deal with inner BrepFace loops (that also does the C#). This is a bit tricky mind to do with standard GH components (if you are a beginner).

2.2. Convert the trimmed surface (a BrepFace in fact with inner Loops) into some mesh.

2.3. Feed all things (cables, perimeter edges, mesh body stuff, anchor points) to Kangaroo engine.