# Catenary vault simulation

Hello,

As some may already know, Gaudi pioneered the use of catenary curves to optimize the vaults of his cathedral: he would use chains weightened with sandbags attached to the roof, and reported their curve upside-down on his plan. Here is what it looks like IRL: http://en.wikipedia.org/wiki/File:Maqueta_funicular.jpg

Now my questions is quite simple: is it possible to create a similar model in Blender ? Eg: draw a flat vault, attach different weights and launch a simulator, to see how it curves ?

qwerkus

you would need to simulate the math equations for it

there was in 2.49 a Catenary curve but it was the unloaded type not the laoded one under tension!

now if you have an example showing how to solve these equations
cause i don’t have one example right now with me
i can see if i can make a small new script for this effect

by the way this requires an iterative process to determine the solution to a Transcendental_function / equations!

salutations

Hello,

Thank you for your reply. Wouldn’t it be enough to model a curve made of elements with different densities/weight, as described here: http://en.wikipedia.org/wiki/Catenary#Nonuniform_chains ?

Than I wonder if you would have to script it from the scratch. The soft-body panel already offers the possibility to simulate the effect of various weights attached to Vertices/Edges/Faces of a mesh. Would it be possible to adapt this function to show only the equilibrium point of the model, once gravity/weights are attached ?

Again, thank you for your time,

qwerkus

well it’s easy for one chain but if you want it for a vault ceiling
this represent a much more complicated set up
and might require a much more advance model using finite elements analysis!

unless you already found such a python program for a vault celing!

and BGE might be able to represent it in blender but it wont do the proper structural calculations

salutations

As it does the type of job I’m looking for, I contacted the author, which kindly offered me to share his libraries (java) to write a blender add-on. This way, all there is left to do is writing an interface to interact with the model: expected functionalities would be:
-create a catenary chain/surface in either mesh or curve mode (a snap option would be amazing)
-change weights on idividual knots
-an finally a ‘simulate-it’ button, which calculates the model.
I keep this thread updated, as soon as I get the libs.

qwerkus

ps: maybe this thread should be moved to the scripting subsection ?

but is it for a simple chain loaded catenary simulation
or for a vaulted ceiling which would be much more complicated ?

mind you if it is it would be interesting to have it in blender

let us know if you began working on a new script for this
that would be interesting

have you seen the script for a simple unloaded chain or rope in script section?

if you open a new thread let us know so we can follow it

thanks for feedback