Cornerpins and keystone

Aug 17, 2011 at 8:26am

Cornerpins and keystone

Hi there,
please first excuse me for my approximative english.
I red some topics about keystone and cornerpins :

It appears to me that the result does not follow the perspective's rules. I mean that using or is not a proper solution to achieve a keystone : it creates distortion on the source that are not acceptable.
Have a look at my examples below (2).
Beside, of course, using (3) produces correct results.
And there's a tool in Photoshop, named 'distortion' (in the french version), that allows you to use cornerpins and produces a correct result (4).

So, my questions are :
Is there some jitter object which could make correct keystone by using cornerpins ?
Any idea what sort of maths I should implement into a patch using to get the good result ?

Many thanks,


  1. keystonedemo.jpg
Aug 17, 2011 at 10:33am

Hello Eric,

Thanks for addressing this bug.
It was already discussed here:

But there seems not a proper solution.
Hopefully cycling will fix these bug soon.
Or is it a feature :-)


Aug 17, 2011 at 2:36pm

Thanks KS,
it does not appear to me as a bug, but it would be a nice feature.
Waiting for Cycling’74 is nice, but does anyone have an idea about some maths that could be implemented in a .maxpat ?


Aug 19, 2011 at 10:51am


I think this is definitly a bug.
There is no software on the market,
which deforms the content in that way.
i personally testet: Photoshop, Final Cut Pro, After Effects, Module8, Resolume, Open Frameworks …

Is there someone, who needs this strange deformation ?

From my point of view this should be fixed.

Just my 2 cents,

Aug 19, 2011 at 4:47pm

here is a sample project with sources, how to do a proper distortion with openframeworks:

here is a screenshot made with this project: flag_openframeworks.jpg

perhaps you can do your project with of.
its a shame, that we can not manage such a simple job with jitter :-(


  1. flagopenframeworks.jpg
Aug 20, 2011 at 1:24pm

Many thanks dupecom.
Unfortunatly, I’m unable to do anything with c++.
But perhaps someone could implement this code into a max object that could be named jit.keystone ?
That would be so nice !


Aug 24, 2011 at 5:01pm

+1 for the

Aug 25, 2011 at 10:58am

Hello C74,

I am a jitter user and i want to realise a video mapping project this year.
For doing this it is very important to have a proper keystone distortion of
the movies.

My question is: Are you going to fix this issue with the next version of max ?
It would be great to get an answer, so i could plan which technology i have to use.


Aug 25, 2011 at 11:49am

I’m interested in this answer too, for similar reasons.

Aug 25, 2011 at 11:55am

Perhaps an easy solution would be to let us adjust the corners of a

Aug 25, 2011 at 2:21pm

+1 for this feature on videoplane and others. :-)
for same reasons than others. ;-)

Aug 26, 2011 at 1:43am

I’m so pleased to see there’s so many people interested in this feature.
Working with videoplane would be less interesting than with nurbs : for video mapping, you also need to be able to adjust barrel correction and some other geometry.
The more advanced solution is probably the Watchout’s tool (have a look at the .pdf below). Well, license is EUR 1624,00 per computer…

Aug 26, 2011 at 2:13am

Our team presents a monumental show these days, with video mapping, lights, sound and pyro. You can see some photographies here :é-2011-à-Laon-02/235710029804812?sk=wal
or here :

Place : Laon’s cathedral, Laon 02, France
Projection with 4 Barco
4 mac mini to display the movies
I created the soft that drives the show thanks to MaxMSP/Jitter. Server and clients, via ethernet. A Macbook Pro drives the 4 mac mini via timecoding, and add geometry correction thanks to It drives ProTools (for the sound) via midi timecode and also send timecode for the DMX.
Finally, all is working perfectly.
Snapshots attached.


[attachment=169661,2570] [attachment=169661,2571]

  1. vnserver02.jpg
Aug 26, 2011 at 2:56pm


been doing videomapping with max for ±3 years now

all done with max/msp

at first i also tried do do it with nurbs or quads .
finaly i just culculated a vertex grid in a matrix and corrensponding texture matrix

can control the gui with my ipad by using touchosc


  1. mjmap.png
Aug 26, 2011 at 11:43pm

Hey, this one seems to be very interesting ! Nevertheless, I’m not sure to be able to reproduce… ???
What is the small form at bottom left standing for ?

Aug 27, 2011 at 12:37am

the interface shows all of the mapped shapes at the same time . ( in this screenshot there are just 2)
I did do shows/setups with >20 shapes

like this one
which is done with two projectors

Aug 28, 2011 at 12:55pm

I also vote for the feature. Nice to hear that there are solutions out there but what about sharing them?

Sep 5, 2011 at 5:47pm

+1 for sharing. :-)


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