Grasshopper

algorithmic modeling for Rhino

Attractor Cube: Meshing, Math Questions, Keeping straight boundary on grid with attractors

Hello World !!

After seeing Marios Tsiliakos Ora Ito's like definition i was very inspired. The thing is that i don't like to copy things made from someone else and even more things that i don't understand completely (i just don't get the math part...).The code can be found here: http://digitalsubstance.wordpress.com/subcode/

So i decided to make my own definition: a cube deformed by 5 attractors and i was wondering if someone can help me solve the meshing at the end of the definition because when i bake it, it gives me an open mesh and i don't understand why ? Waterfall meshes are not suitable for 3d printing... I don't think i've used the clean, weld, and unify faces in the good order ? Maybe there is a problem with the surfaces ? 

Secondly i'm not very proud of the result of my cube because it's so deformed that it is a not a cube anymore... so i was wondering if a square grid of points can be deformed by an attractor but still keeping the straight boundary of the grid ?

I had an idea to make that: i make my points, create the vectors between the grid and the attractor points, calculate the distance between the grid points and the attractors: it gives me a list of distances that i remap to control the strengh of my attractors. On the other side i calculate the distance between the boundary of the grid and the grid points and it gives me a second list of numbers. So i wanna average the two list of numbers in such a way that the closest it is to the attractor it takes the distance from the first list and the further it is from the attractor (so the closest it is from the boundary) it takes the distance from the second list ?? I'm sorry for my bad english but even in french it's little bit hard for me to explain it ;). So what can i do to have a grid attracted by a point without moving the boundary points ??

And please don't tell me to cull the boundary points first, to deform the grid and to rebuild the grid after... it gives an ugly cube face at the end, even with a lot of polishing with weaverbird... 

If someone has another idea to achieve that please tell me ;)

The first definition "CleanCubeMeshingHelp"is a little bit heavy so watch out if you have a small laptop (any ideas to make it work faster are welcomed !!)

The second one is the one with the two list of numbers.

Also a last questions: what is and when to use the "blur number", "interpolate data" and Weighted Average" under math utilities ??

Thank you in advance for you answers and i apologize for my lack of vocubulary.

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??? 

Anyone has an idea to solve my problem ? Please help

Hi Nenov,

all I can come up with is remapping the second list from 0 to 1 and multiplying the 2 lists, so the farther away a point is from the edges the more it will move. This gives some unpleasant results when the attractor moves far away though, but hopefully it will assist you in the right direction.

As for the first question I am afraid my knowledge in meshing is limited...

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Thank you very much for your help Nikos ;)... now i see it's not the good way to keep the boundaries... i will try to find something else...

Hi Ivo,
here is what I came up with, using Kangaroo (still 0.97, pre-zombie version). Hope it contributes to your solution.
Note: I used far less faces, and the part where I make the stepped insets is just a first try that doesn't quite work as planned...

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Thank you Pieter,

I 'll start by remaking your def, kangaroo is a complete new world for me, never used it much... Do you think the deformation can be exponantial ??

Exponential how Ivo? I don't understand. Did you try to implement that yet? If so, please upload the file to investigate.

I was wondering if the deformation of a face can be strongest without collapsing with the other faces... if the closest points to the anchor points can behave like a more heavy point to move... i don't know if my clear but for now your def was very helpfull, i manage to make almost what i intend to ;). 

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Now the problem is there is not enough deformation and i don't know how to make bigger deformation without collapsing the faces between them... if anyone has an advise it will be nice.

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Hello

i cannot open the definition at the moment, but i would like to suggest something that might work, which is setting separate spring force for the cube boundary with multiplied stiffness compared to the others (or divided rest length) until you have the deformation you are after.

cheers

alex

I'm guessing (how much deformation is enough?) you'll want to play with the distance of the attractors to the cube, the rest length formula and the repulsion settings. I'll attach a little changed definition, main change is in the rest length part (my interpretation of exponential). I didn't see (or should I say - couldn't find;) any exponential calulation in your last two uploads.

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