# Loft issue

Hi,

I’m trying to create a loft on an expandable geometry (otherwise scaled geometry).
However, with the method I used, I encountered multiple issues:

-If I am to resize the base curve, it will change the list of the curves at which end I placed a frame, therefore, the loft won’t properly work on any stage of expansion of the base polygon.

(let’s suppose the loft was done properly)
(and what happens if resizing the base geometry)

Is there any way to have have a consistent direction of the frames (i.e. all the x-axis direct toward the lower side of the rhino World plane)?
And is it possible to keep the loft while resizing the geometry of the base?

Rails.gh (21.2 KB)

frames/planes are usually created by two vectors (x and y axis) and a base point. If you create a plane the y-axis will automatically get corrected in order to ensure being orthogonal from the x axis. So the x axis will always be fix.
(Under the hood the following will happened: The cross-product of the x and y axis will get created, this yields the z axis. Then the cross-product of x and z axis gets created, which then yields the corrected y-axis. This way all three axis are orthogonal.)
Why is this important? If you want to create planes you always need to feed in the these 3 parameters.
The origin = point on the curve (at t)
The xAxis = the tangent of the curve at the origin (at t) - needs to be fix
The yAxis = polygon center - point -> in 3d set z coordinate to 0

depending on the curve direction this will return positive or negative z axis. You just need to recompose the planes then.

Here is a´n example. I couldn’t open your definition, so I drew my own curves

Rails_cor.gh (14.3 KB)

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maybe this curve example is a bit unlucky. (Twisted areas)
This one might me more suited:

Rails_cor2.gh (11.7 KB)

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@TomTom hello tom i like your theme of grasshopper background. Could you able to tell me how to achieve this kind of theme

In order to change the colour of the canvas you can override the “grasshopper_gui.xml” in your Grasshopper folder.You can also change the wire colours in there.
As an alternative you can also download @Michael_Pryor “Pallete” plugin (found on Food4Rhino).
The only difficult thing will be randomising the wire colours. I haven’t made it public available. Its done by re-implementing the wire drawing process.

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This is, that the base geometry serves more as “rail” for the “zigzag”. The actual loft made at the end of the segments from the zigzag.
Basically, it’s to emulate the deployment of a beam if you may.

Here’s the complete definition of what I’m currently doing.(I marked where is the place of the loft issue)
(but had the same issue with perp frames in the 2nd group for example)
hexarails.gh (391.1 KB)

as said, I cannot open your definition due to missing plugins(…and I won’t install them).

I may understood it wrong, sorry. Its more about a principal approach. Its about orienting planes the right way in order to guaranty right orientation of the sections. Isn’t it possible to create an abstraction your problem without any plugin usage?

Edit this is what I understood:

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