Rotate Panel with Vector

Hi,

I am trying to rotate a series of panels to an attractor point. So the start point of my panels rotates with the attract point. I am hoping that the rotation can be dictated by a vector (eg. sun angle). I have attached what I have got so far.

I have had a look at older posts, and this post details what I am hoping to achieve.

I have attached the image for your reference.

Much appreciated.

Attachments:

planerotation02.jpg, 308 KB
My Attempt.png, 41 KB

Replies to This Discussion

Permalink Reply by Danny Boyes on April 16, 2011 at 7:01am

Can you post your 3DM and GHX files to play with?

Permalink Reply by Eleanor Wong on April 16, 2011 at 7:12am

My apologies.

Attachments:

Lourves Rotate.3dm, 44 KB
Lourves Rotate.ghx, 158 KB

Permalink Reply by Pieter Segeren on April 16, 2011 at 7:21am

Didn't see these (^) yet, still hope this helps.

Attachments:

Eleanor_PSG.ghx, 89 KB

Permalink Reply by Eleanor Wong on April 16, 2011 at 10:43am

It works, thank you!

Permalink Reply by TheChosenOne on April 16, 2011 at 7:39am

http://grasshopper3d.ru/forum/topics/klasterizuemsya-1?commentId=40...

Permalink Reply by Danny Boyes on April 16, 2011 at 7:48am

Is this the right link?

Permalink Reply by Danny Boyes on April 16, 2011 at 7:46am

Hi Eleanor,

You are rotating the first panel only about all the other panels, which I don't think is intentional. Also you are basing the rotation on distance from the attractor rather that direction. If you want the panels to face the attractor point, like the other post, then you need to:

1) create a Vector between two points. Vector>Vector>Vector2Pt

2) create a reference vector to measure against. Vector>Vector>Unit X

3) Measure the angle between vectors. Vector>Vector>Angle

because the angle between two vectors is always shown as the reflex angle you will need to calculate the direction of rotation separately.

4) Calculate the Cross Product of the two vectors. Vector>Vector>Cross Product

5) Unitize the Cross Product. Vector>Vector>Unit Vector

6) Extract the Z component of the Unit Cross Product. Vector>Vector>Decompose

7) Multiply the Z component (either 1 or -1) with the Angle. Maths>Operators>Multiplication

8) Rotate each panel about its base point by the angle to the attractor. Transform>Euclidean>Rotate

Permalink Reply by Eleanor Wong on April 16, 2011 at 10:45am

Thank you, that was very thorough.

Permalink Reply by G on June 8, 2011 at 4:18am

Dear Danny

I have using your example here to calculate a similiar scenario. It works! BUT

i dont really understand a few steps or why it works.

Would it be possible to explain the "why" for steps 3,4,5 and especially 7

Would be awesome if you can help me understand this

Kind regards

Gordon

Permalink Reply by Danny Boyes on June 8, 2011 at 7:15am

In this example the vectors are in the xy plane and the cross product for two vectors in this plane will either be up or down. It will be +ve Z if the angle between them is going anti-clockwise and -ve Z when going clockwise. So unit-izing the result will give either a 1 or -1 in the Z component which can be applied to the actual angle and give direction for rotation in the world axis.

More about the cross product and right hand rule http://en.wikipedia.org/wiki/Right-hand_rule

Correction to the above post should be acute angle instead of reflex.

Permalink Reply by G on June 8, 2011 at 7:36am

Thanks Danny !

Permalink Reply by Andrea Hendrickson on February 20, 2016 at 9:22pm

Danny,

I am trying to do something similar except I'm trying to rotate the scaled surface in relation to the attractor point in the XYand Z direction. If there is any advice you can give on my scrip that would be great.

I'm trying to create something similar to this project:http://www.dezeen.com/2009/05/20/3d2real-by-ilek-students/

Thanks

Attachments: