Grasshopper

algorithmic modeling for Rhino

I was wondering if there is a component or a process by which two separate, non adjoining meshes can be merged so that a new mesh geometry is created between them based on a set of closest point vertices or other parameters. 

In the attached image I have two distorted models of the Burj al arab and I would like to find a way to create a mesh geometry which links the two together (as illustrated in the second image). Ideally this could be based on a set of vertices or parameters of my choosing. 

I realise that these are two fairly complex meshes to join, however if it could be done for simpler geometry, for example two mesh boxes (basic GH definition attached) then this may help to understand the process; if such an option exists. 

Thanks, 

Tom 

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Hi Tom,

It is still not very clear how you want to 'join them exactly? In the case of the mesh boxes, can you draw it in rhino? do you want a new box between them? or just lines? or mesh faces? Is it always joining mirrored geometries - this might make the exercise easier?

Have you tried millipede geometry wrapper? I showed an example in class 3 for DS10. Or kangaroo shrink wrap?

http://vimeo.com/31082350

JAM.d 

Hi Andrei, 

Thanks for getting back to me. I tried the shrink wrapping successfully but I'm not quite sure it is having the desired effect. It's quite hard to explain how I would like the meshes 'joined' as this is kind of unknown to me, which is why I wanted to look for a tool or script that might generate some geometry between the two. The fundamental principle is that the input meshes must retain 90+% of their original geometry (ie not deformed into an approximated wrapped shape) but be joined together by some sort of mesh geometry which acts as a link between the two shapes. The form for this could be highly abstract and doesn't need to conform to any parameters other than allowing the original meshes to be highly visible. I hope that makes sense, it may only be clear in my mind now that I have pursued it this far!

With regards to the geometry wrapper, I found the example file that you sent us and attempted to plug in similar variables with my meshes, however the values returned by the geometry wrapper are constantly zero, no matter what I seem to change. 

I am currently plugging the mesh into a bounding box, which forms the box for both the geometry wrapper and iso surface and then inputting integers for the remaining parameters, though I'm not quite sure what actions these are performing. Would it help if I could send you my definition? I'm currently trying to internalise my meshes, though my rhino keeps crashing when I try! If you aren't able to follow any of the above let me know and I'll try and put together some simple diagrams that may explain it better. 

Thanks, 

Tom

Hi Andrei,

I've managed to simplify and save my definition attached, if that helps!

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Hi Tom,

I am really sorry but I don't fully understand how you want to join the two towers.

Would you be able to post a sketch of your idea?

Hi Arthur, 

Sorry I'm finding it a little difficult to explain - attached are two simple sketches which hopefully illustrate the idea behind what I'm trying to achieve. Though I'm not too concerned with how this is achieved or how it will look. I'm mainly trying to link the two anamorphic objects so that they read as one. 

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Hello Tom, 

I think I get what you are trying to do. If it's something hard to explain, it will generally be difficult to resolve as well, and I am afraid I don't know of a component that will do this for you in one go.

I still think shrink wrap might help to get the connecting meshes- but you will need a much denser mesh box. Or you have to design the rules of your algorithm in simple statements. Something like this:

For each vertex of mesh A, identify the closest 2 vertices from mesh B; If the distance is below a threshold value, make a mesh face with these 3 vertices / or maybe add them to a list to create a mesh at the end. after you create your connecting mesh, you will have to find a way to optimize it, and join it to the original meshes.

It sounds to me like it will be a complex definition. And as a suggestion, the models you are using are very heavy - maybe use some simpler geometries to design your definition first?

Hope it helps

Andrei

I agree with Andrei, if it is hard to explain, it is often hard to find a solution. It seems from your sketch that you are linking the two buildings with a single surface that is tangential with the facades of both building - A bit like the "blend surface" tool on Rhino? If you can extract the curves that you need to connect and maybe some more curves on the facades to get a tangent axis then you can definitely do a loft that follows the geometry of the two building?

Thanks Andrei & Arthur, I'll try and break it down into more simply defined operations. Just wondered if there was a tool that approximates the kind of thing I wanted - there often is!

Andrei, I definitely think the idea of using less heavy models to test is a good one. Will have a go and see what I can come up with. 

Thanks again for having a look at it!

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