projecting a curve onto a plane in a specified direction

i want to project a curve onto a plane in a specified direction by using:
- a rhino curve
- a plane-component to project onto
- and a vector-component for the direction

the project-component from the x-form/affine section only lets me project in a fixed direction (normal to its projection plane).

the project-component from the curve/util section only needs a brep input to project onto.

any ideas, how i could manage this?

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Permalink Reply by Alessio Erioli on May 24, 2009 at 3:48am

Hi Roberto,

one possible way could be to extrude the curve along your chosen direction (you decide the vector) and then perform a Brep-Plane intersection.

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Permalink Reply by roberto gagliano on May 25, 2009 at 1:44am

hi alex,
interesting solution, thank you.
the background of my request is:
- i want to use as many gh-generic elements as posible
- at the same time i want to keep the overall amount of components as small as possible

at the moment i use a project-component (curve/util section) with a rhino-surface to project onto, which i dont really like (the rhino surface is not infinite, and its visibility cannot be controlled from within gh), but i can do it with only 2 components (curve and project) plus the rhino-surface as brep-input.

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Permalink Reply by roberto gagliano on May 25, 2009 at 1:56am

just realised, that the the project-component (curve/util) accepts a gh-plane-component as b-rep input without showing error messages (which wound be, what i am after)

but it does not show any result! (projected curve)
am i doing something wrong?

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Permalink Reply by Alessio Erioli on May 26, 2009 at 9:14am

Roberto,

I'm afraid GH needs a surface, not just a plane definition: I just tested by adding to your scheme a planar surface defined from the input plane, it's just one component away from yours. Of course my cognition might be incomplete and maybe someone can suggest better solutions.

Cheers!

.A.

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Permalink Reply by roberto gagliano on May 26, 2009 at 11:56pm

not sure, if i understood, what you suggested, but the planar surf based on the input plane wont work here, it asks for planar curves as input

can you please add a screenshot of your solution here?

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Permalink Reply by Alessio Erioli on May 27, 2009 at 12:47am

Sure Roberto, here are the screenshots of the definition and the result. Sorry I misled you by incorrectly calling "planar surface" the "plane surface" component...

Of course in my definition a lot more components appear but just to define the plane and the projection vector by points so I could easily change them, but you can inherit them as well as using the way you defined them.

Here they are:

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Permalink Reply by roberto gagliano on May 27, 2009 at 1:53am

as far as i can see, to define a plane surface i need at least two components in addition to the plane surface itself: a plane and an intervall. if i use the rhino-plane its only one. moreover the plane surface is not infinite as well...
what i am after is more like ProjectToCplane in rhino.

one reason to avoid many components is the crowded canvas.
a possible solution (i know this from wirefusion, a software to create 3d-web-contenet, also working with wires) would be to group components into containers. is this also possible in grasshopper?

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Permalink Reply by Alessio Erioli on May 27, 2009 at 7:36am

Well, I used components to define data but you can as well set the data you need (such as a number or an interval) directly in the components by right-clicking on x & y of plane surface component and set the interval you prefer.

In the top definition curve, plane and vector are inherited, but you can as well define them directly in the parameter components (as I suppose you did in your definition). The bottom definition takes plane and plane surface components and chunks them into a cluster (cluster buttons are the ones left to bake button), which might be useful for saving canvas space and/or overcrowding. The final curve parameter component stands only for output clarity.

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Permalink Reply by roberto gagliano on May 27, 2009 at 7:59am

wow, thanks a lot for all the info!
it will take some time to check it out...

cheers roberto

Permalink Reply by Dirk Anderson on May 27, 2009 at 8:49am

Attached is a VB that projects curves to a plane. The script still needs a few minor tweaks such as an inclusion for 3d curves and a iterative collection of brep to curve projections (currently, if the curves overlap each others bounding boxes they will project over themselves). Will update soon enough with these fixes + the inclusion of multiple vector + plane inputs

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