Warping the Renderer output so you can project on a wall and skew it?

vvvv beta question
1

Hi there, how would I go about this?

I’m using a projector and it’s not directed straight at the wall but more at a 40 degrees angle to it.

My projector only has options to adjust the vertical skewing but not the horizontal skew.

Is this something that vvvv could handle in realtime? Ie outputting a video file and giving me the options to adjust the skewing while it’s playing until I get it to look unskewed?

The transform3D gives me some control when plugged into the “View Transform” Pin of my “Renderer” Node, but I can’t get it to “skew” as in scale one side smaller while other is larger, if that makes sense?

2

basicly you can try with 3d rotate, just imagine you need to orient the quad as you looking from projector point. Homography node is used for that

3

huh. have a look at Homography (Transform 2d)

4

Perfect, thanks guys! Problem solved.

5

@antokhio and @others:
Is Homography (Transform 2d) like a rotation? Or like a distortion?

I’m a bit confused about View and Projection Pins on Renderer (EX9)

Where to apply the homography when using a Camera (Transform Softimage)?

Now I’m achienving this thanks to * (Transform) but maybe also the Distorsion on Camera node can work as well…

…Could anyone point me in the right direction?

Keystone and Camera (9.3 kB)

6

Make a homography node, highlight it and press F1 to get the help patch. That will show you how to connect it to the renderer.

7

@sune
I know very well the help patch of homography, I always copy and paste from there. I made also a Keystone for myself…

In the help patch the pin used on the rendered is the Projection…

…I was asking:
When there’s a Camera involved that needs a _View _and a _Projection _, Where to link the homography?