Grasshopper

algorithmic modeling for Rhino

extract items from one list, using as filter values on another list

Dear all.

I apologize 'cause maybe my question could appear stupid, but I'm new here...

I have a cubic array of points from grasshopper and a mesh modeled in rhino.

I would like to list all the points included in the mesh, excluding all the external points.

I used the "mesh inclusion" component, and now i have a list true/false, same length of the list of all points. What I'm not able to do now is to extract the points of 1st list that have a "true" value in the 2nd list. I wonder that it should be very easy, but still I don't know how to do it.

I' d really appreciate your help. Thanks.

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Replies to This Discussion

Hi Marco,

You can use a [CullPattern] component and plug the points in L and the true/false list in P.

Hi Nikos Tzar, very kind.

I finally tried with the "dispatch" and it was working, but now with the "cull pattern" it's even faster.

Now I've got the list I wanted.

Since you are so kind, I try to take profit and ask you another question:

With the list of points I would like to make this procedure:

- group all the points with same x,y coordinates (I mean all the points that belong to the same vertical column)

- know how many points are in the same column

- know the z position of the highest and the lowest

Something like: "there are 8 points on the column with X=200 and Y=50, the first  point has Z=20, the last has Z=130"

is there a way to do that? I feel like I'm getting closer, but can't achieve it...

thank You for your attention

Hi Marco,

The problem with Box Array (I assume this is the component you have used) is that it outputs a single list (no data tree structure) which makes it difficult to group the points afterwards (it is not impossible but quite lengthy).

I would suggest replacing the Box Array with a SqGrid (or a RecGrid if you want differentX and Y size) and then do an ArrLinear for the Z dimension. This way you can have your grid points grouped and sorted throughout your definition and you can easily query the properties you want:

If you are having any trouble implementing this to your file, then please upload your file so I can locate the problem.

Cheers,

nikos

Thanks alot Nikos.

It was exactly what I needed to know. I used and implemented the composition you sent me, also adding the output of some needed info; now it's fully working. Sinthetically, we have to product a big chandelier for an interior design, with the shape of a cloud. So I had to fit the space of the mesh with plastic shells where needed, but also to explain to the manual assemblers how many shells for each column and in which position. Now it's working, I just wait for the final mesh form the designer. Here I post the grasshopper file.

Again, thank you so much.

Attachments:

Thank you for the feedback,

the mesh in your definition is not internalised so I can't see the final output but your project sounds interesting, so I'll be waiting for some pictures of the real thing!

cheers,

nikos

Hi!

The mesh is not internalized because it has to be defined yet. Anyway, you can try with every mesh you want. Max dimensions are defined in the sliders on the left (I used dm as unit, cause the plastic shelves are 90mm diameter). Position should be x and y positive, z negative (being for a chandelier, it's hung to a net frame on the ceiling).

I wait for your feedback. It's only the second work i did with grasshopper, but It has been a great satisfatciotn for me...

regards

I tried it with a simple shape (icosaedron) and it looks really nice!

I believe it is quite advanced for a 2nd project, congrats!

Only tip I have for being able to have faster feedback from the definition is to have the grid as small as possible around your object and maybe to add a data dam before the [boundary surface] component, as this is the most heavy operation.

cheers,

nikos

ps. still looking forward to seeing some photos from the real thing!

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