Chaos Corona Forum

General Category => General CG Discussion => Topic started by: lupaz on 2018-03-28, 18:11:59

Title: Dealing with cylindrical correction of volume anamorphosis
Post by: lupaz on 2018-03-28, 18:11:59

Hey guys,

Does anyone know if there's a way to correct cylindrical distortion from renderings within 3Ds Max?

(https://www.dxo.com/sites/dump.dxo.com/files/dxoimages/photo/academy/tutorials/vp/understanding-volume-deformation/fig-19.jpg)

Title: Re: Dealing with cylindrical correction of volume anamorphosis
Post by: maru on 2018-03-29, 14:10:50

If you create a Corona Camera, you have "distortion" rollout there and you can control the cubic distortion amount manually. The drawback is that when using extreme amounts you will end up with a circular crop in your rendering. I am not aware of any "automatic" way to do it.

Title: Re: Dealing with cylindrical correction of volume anamorphosis
Post by: lupaz on 2018-03-30, 01:29:24

Hm. Thanks Maru.
DxO Viewpoint has a pretty cool feature to correct this. I wonder if Corona could have a post effect that uses a similar algorithm. Just an idea,

Title: Re: Dealing with cylindrical correction of volume anamorphosis
Post by: piotrus3333 on 2018-04-01, 08:32:46

try this texture as distortion map in camera:
https://we.tl/8G2rSuMg8m

1920x1080 resolution should work best with this one.

Title: Re: Dealing with cylindrical correction of volume anamorphosis
Post by: lupaz on 2018-04-06, 17:07:05

Quote from: piotrus3333 on 2018-04-01, 08:32:46

try this texture as distortion map in camera:
https://we.tl/8G2rSuMg8m

1920x1080 resolution should work best with this one.

Thanks Piotrus! The image gets the barrel look with that map, which for architectural images is a no no.

Title: Re: Dealing with cylindrical correction of volume anamorphosis
Post by: piotrus3333 on 2018-04-06, 17:30:57

it's just a sample made for 8mm lens camera so the look is pretty extreme. the point is you can put any projection you can imagine into texture like that.

Title: Re: Dealing with cylindrical correction of volume anamorphosis
Post by: lupaz on 2018-04-06, 18:55:37

Aha
I hope I'm not one of those that ask questions that can be answered with 5 minutes of googling, but:
How do you make those textures?

Title: Re: Dealing with cylindrical correction of volume anamorphosis
Post by: piotrus3333 on 2018-04-06, 19:34:26

add two gradients. black to red and black to green. red gives you X and green - Y. render that in resolution you need.
16bit minimum and full float optimal - you need separate values for all the pixels in the image and accommodate for distortion.
than distort it to your liking with whatever software you have (example attached).