Forum

Rotation and vectors


#1

Hello everyone!

I’m a newbie to vvvv, so my 2 questions could seem very easy. I think my problem lies in some global vvvv concept misunderstaing comparing to other modular graphics software (i use grasshopper a lot)

  1. Let’s say I have a straight line going along X-axis starting from origin, so it has start point A coordinates {0, 0, 0} and end point B coordinates {1 or inf, 0, 0}. And I have a point C somehwere in the 3d-space width given coordinates {x, y, z}. I need to rotate my A-B line to make point C lie on A-B line (in other words, simply forward my line to point). I don’t need to construct it graphically, but I need to get a proper transformations (as I’m going to use it for other objects) How can I make that?

  2. Could you please briefly describe me a vector concept in vvvv? I mean, for example, when I’m using Vector (3d join) node it requires only XYZ coordinates and I don’t quite get how vvvv interprets this data. Is it a point coordinate or a usual vector starting at {0, 0, 0} and going to defined {x, y, z}?

Thank you!


#2

point’s to vector is what cha looking for, vector3 in general just a point coordinate


#3

Thank you for your answer! But I still don’t get it :) I’ve made a simple patch to demonstrate process (line should start at white sphere (and it does) and go through red sphere). I think there’s some dumb mistake but I don’t see it :(

point2vector.v4p (16.9 kB)


#4

hi. it’s really not obvious what cha trying to achieve there
i’d suggest u check that page first:
3d vector mathematics
and then post if u have more questions…
and if u just want line from one point to another u might look at LookAt transform


#5

the line module does the trick. see patch

point2vector.v4p (10.9 kB)


#6

I, too, don’t quite get what you want to do. Is the problem the bit where you…

need to get a proper transformations (as I’m going to use it for other objects)

and you fear gregsn’s suggestion (posted while I was typing;) will not help you? Maybe just start working on the other objects. Your problem just might disappear :)


#7

Thank you for a suggestion Antokhio, this article is really helpfull in uderstanding vectors (I saw it before but didn’t fell that I need toread it). I guess it can be done using formula in Dot Product section (I haven’t tried it yet).

But I guess I’ve found a solution - simply use ToLine node which does a trick (I’ve attached patch with quick animation to show what I needed). I can’t say it’s very clean as I had to make some manual transformation along X axis, but for now it also fine.

The reason I needed not just to make a line like Gregsn suggested is that I needed to get a transformations only - I’m working with Intersect node right now and it requires a transformation for the ray. And I have a spread of coordinates on both sides constantly moving around 3d-space, so I needed to calculate the position and rotation amount for each ray.

point2vector.v4p (21.6 kB)