# Gravity node

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On 11/14/2019 at 11:00 AM, GRZEGORZ said:

Hi, all.

I had been inspired by the "Create and Rotate a line in polar coordinates" topic, and came up with a idea of creating node that mimics gravity. And that's the result, as a simple Marionette Object.

How it works:

1. Input point as "Gravity center".

2. Input list of points to modify.

3. Gravity value. Defines "strength" of gravity force. 0 = nothing happens, 1 = point will be moved to the  gravity center. Positive values moves points away from gravity center, negative towards it.

4. Radius value. Defines the area where points will be modified. Points outside this area will remain unmodified. Works as a remap of min and max values of radius and transforms it into 0-1 factor, that multiply gravity value. Gives an effect of different gravity strength depends on distance from gravity center. The further the point is, the less gravity will affect it.

Hope you will enjoy it.

I like this idea and wonder if it could be made to generate catenary curves?

@mjm Not in this form. Node I made was designed as intuitive tool for fun, not as a mathematical one. Inputs does not represents real strengths.

But it might be an interesting challenge to make something like you asked. I will give it a try in my free time.

Catenaries are one of those things which crop up irregularly in my design practice and there's currently no easy way to draw one.

I needed a catenary in vwx to describe a cable hanging between two posts. I drew a poly line cubic spline - top>midpoint>top. Then I found an online catenary generator, input the parameters for same span and sag, saved the resulting pdf image and ported that into vwx. The spline fit on the image. Same process confirmed spline fit to image if post tops not same height.

Math correct? Not sure. But close enough for my use.

-B

This is one of DomC's that may help.

9 hours ago, Benson Shaw said:

I needed a catenary in vwx to describe a cable hanging between two posts. I drew a poly line cubic spline - top>midpoint>top. Then I found an online catenary generator, input the parameters for same span and sag, saved the resulting pdf image and ported that into vwx. The spline fit on the image. Same process confirmed spline fit to image if post tops not same height.

Math correct? Not sure. But close enough for my use.

-B

@Benson ShawThat'll work for me. Much appreciated.

Thanks for sharing. Really ambitious work with the gravity node, respect!. If this would be futher on possible in the z-axis as related elevation, as a sheet with thickness (2 - 20 mm), might also be great fun .  This could be very helpful an idea for  "doors with belly" (furniture / room door). Friendly regards , BerndL.

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