2D mapping problem

something for the math talents. i have a distorted coordinate system and i want to map every point within the system to another ‘even’ coordinate system. see the attached patch for more details. a bit like homography i guess.

i’m perfectly stuck with this right now :/

2Dmapping.v4p (8.2 kB)

why don’t you use the homography node, it solves exacly that problem…

because i want to extend the idea, transforming coordinates of a grid with more than just 4 corner points.

found somthing http://www.cescg.org/CESCG97/olearnik/txmap.htm

the output of the homography node is a transformation from the system defined by the first 4 points to the system defined by the second 4 points. with the output matrix and ApplyTransform (or *(3d) ) you can transform any number of points from one system to the other. and the node is spreadable… still not solved?

whats your application of it?

tonfilm, you are absolutely right, i had a second look at homography just before i read ur message. i just try to work on a better calibration for my multitouch.

ok, i think i’m close to what i want but its not working 100%. the transformed point (move mouse in left renderer) is jumping between the 2 areas.

i have 2 guesses what the problem is. first the idea of switching, if the point is closer to the centre of each cell, doesn’t work too well. and the other problem might be the two systems simply dont fit together at the edge.

maybe you have some advice how this could be solved.

see attached patch

edit: topic closed, i have an alternative solution

homo4.v4p (23.7 kB)

I’m interested in that calibrating thing.

What is the alternative solution you found ?