lens distortion on a panning matte

[anthonyBloor]

I am working on a shot for a short film. The shot involves panning from a live action plate and then 270 degrees through a DMP of a surreal train platform and then back to live action.

I am trying to work out the best way to get the accurate lens distortion that I need to make the flat painting look like a pan.

Is there a good way to work this out? And any tips for some attempting this for the first time?

[homer]

If you mean the distortion between having cylinder mapping instead of flat planner mapping, then it depends on your compositing software. For example with Flame there are easy ways to make this work.

But in general, there are different ways to approach this.
You can paint simple flat images then use something like “Realvis stitcher” to make your cylindrical map.

Or export a temp grid from your compositing software (or 3D software if you have your real footage 3d tracked) and then paint it with distortion.

There are other distortions involve in this process, let’s hope you don’t need to challenge them.

[Ross Forster]

Yeah, I would give Stitcher a shot at this...it can be a tricky subject at times.

[NickATnitE]

There is an interesting article in the tutorials section of this site about nodial point rotation. It goes into the science of lens distortion more, but it does say something about faking it with 2 camera projections onto the insied of a sphere. figure out the start and end shots of your pan and project those images, if that's not enough bisect your painting into more pieces and project. Now I haven't personally tried it yet. but in theory it seems pretty solid.
good luck,

[Sally]

What do you use for compositing?


by the way, Here is Stitcher approach;
http://www.realviz.com/products/st/paint.php
And here is in 3D as "NickATnitE" mentioned.
http://www.mattepainting.org/forum/viewtopic.php?t=109

[anthonyBloor]

I am using shake, I don't want to actually map my painting onto a 3D object, but paint it distorted, and then simply pan and zoom in shake, It is just a nodel pan, but I am not starting with any reference at all really, so i'm not sure if stitcher will be of much help, I was really wondering if there was a traditional painting technique for calculating the distortion in a nodel pan. Having just read the replys i have come up with one idea just, it involves painting 6 projections then using HDRShop to make panoramic transformations, but i will have to try it, and maybe even post a tutorial if its succesful. But I know this used to be done long before computers, maybe its just a matter of obseervation

[edit] Oh and thanks for the tutorial, i am reading it now

[edit again] Oh and hello, sorry didn't introduce myself, i'm a 3d animation grad testing the composoting/matte painting water :P