pathstructure and curve status

Ok,

so i checked the paths and found the curves i wanted to loft had different numbers of subbranches which appears to be the reason why the curves won't loft.

But i don't understand that. I mean, despite the paths of the each curve not having the same number of sub-branches, the results of each path are planar curves, thus i would think the curves should be loftable. But they aren't, why not?
Why does the branchnumber of paths of different objects/terminus subbranches determin their possible proceeding applications?
At the end of the day, aren't curves simply just curves here?

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Replies to This Discussion

Permalink Reply by Alireza Akhoundi on November 30, 2009 at 2:07am

lofting only works with object on the same level of path, so you should make them flat first. maybe it help if you right click on loft icon and tick the flat option of it.

Permalink Reply by Tim on November 30, 2009 at 8:12am

Aah, the flatten option works fine:)
But what's the reason for the same path level condition for lofting if the curves are totally seperate and independend?

I'm just trying to understand.

thanks.

Permalink Reply by Suryansh Chandra on November 30, 2009 at 8:36am

It's not as simple as just inputting curves.. Imagine if you were in need of making multiple lofts with multiple 'sets' of curves... and if it were to behave the way you mentioned (which it did before the 0.6 series), you would always get only one surface no matter how many curves you gave it.

Thus came data trees.. It makes things a bit more complex (& counter-intuitive) initially, but then you realize the real benefit of them once you get more used to it... its been by far the biggest change to GH from 0.5 series to 0.6 series.

The way data trees work is that everything on one path/branch in a tree is treated as one data set, so if you want one loft, just make sure all curves are on one path, but if you want multiple lofts, your tree should have multiple paths with a set of lofting curves in each path.

This makes it essential for all components that take several inputs and give out one output (loft, interpolated curve, curve, surface from pts, etc etc) or vice versa (divide curve, divide surface, etc etc).. essentially where number of inputs are not the same as the number of outputs.

Permalink Reply by Tim on November 30, 2009 at 11:12am

Hey thanks :)

But still, it doesn't explain why planar curves with different paths/histories cannot be lofted with each other, i mean doesn't every component take the data only from its directly preceeding component? Or does every component internally process every inserted path entirely all the way to its terminus subbranch? And if yes, what for? If i use a loft component, doesn't it just need the curve information?

At least it doesn't occur to me, sorry.

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Permalink Reply by Manuel on November 30, 2009 at 11:43am

it doesn't matter what kind of curve you have, for every path it will try to make a loft surface, but for that, you need more than two curves on every set path...
In this way, you can have multiple and different loft surfaces with just one loft component (one surface for every set of curves that have the same path).

Again... go and read -> Page 36 - Cap 8: The Garden of Forking Paths

Grasshopper Primer: http://www.liftarchitects.com/journal/2009/3/25/the-grasshopper-pri...

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