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Adding moving clouds shadows to a still panoramic photo / replacing the sky with a timelapse sky/clouds sequence

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Pedro Luz
Adding moving clouds shadows to a still panoramic photo / replacing the sky with a timelapse sky/clouds sequence
on Aug 8, 2018 at 4:12:24 am

Hi,

Trying to create some shadows effect into a panorama photo, replacing the original sky.
Replacing the sky is easy, no problems.

For creating the shadows in the picture, I duplicate the sky layer, convert it to black and white, flip it vertically and mask it on the ground plane of the photo, and adding key frames for the opacity.
The problem, as expected is that the shadow looks flat on the ground plane of photo, not following the geometry of the ground plane.

Question:
Is there any way to cast the shadows of the new sky into the ground plane, where the shadows can mimic the geometry of the ground plane?
Even if it's not 100% accurate, something that would look more organic and not flat.

thx
pedro


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Steve Bentley
Re: Adding moving clouds shadows to a still panoramic photo / replacing the sky with a timelapse sky/clouds sequence
on Aug 8, 2018 at 4:45:51 am

Well the ground plane probably doesn't have any geometry on it so you would just be projecting on a flat plane - no distortion.
A quick cheat that can sometimes work is to use the Displacement Map effect. Use the ground plane image as the source for the displacement and that will "shift" the pixels of the flipped clouds so that it gives the illusion that they are moving out of the way along stuff in the scene. You may have to precomp your flipped clouds so the displacement operates on the flipped image after its been flipped. There is usually some masking involved too for stuff that shifts off the top of a building, say.

Add to that, or instead of that, you can apply a corner pin (I prefer CCPin as it's sharper) to warp the flipped clouds wider out near camera (for perspective). Again you may need to precomp to have the CCpin operate on the already flipped cloud image.

If you really want to go to town, and you have C4D or C4Dlite you can do what's called camera mapping (or projection mapping). You build simple shapes in 3D that match your picture and then you can literally project your clouds on what is now 3D geometry. The illusion is very convincing. You can also do this with Element 3D.

Can you post pic? We might have some other ideas based on what's in the scene.



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Pedro Luz
Re: Adding moving clouds shadows to a still panoramic photo / replacing the sky with a timelapse sky/clouds sequence
on Aug 8, 2018 at 9:45:16 am

Hi,

By my mistake I did "Report a post" of someone that posted here, that was trying to help me out, I apologize.

I couldn't register all the suggestions that the post contained, would you be kind to post it again?

Thx and again sorry for this

pedro


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Pedro Luz
Re: Adding moving clouds shadows to a still panoramic photo / replacing the sky with a timelapse sky/clouds sequence
on Aug 8, 2018 at 9:59:44 am

This is a reference panorama picture of what I'm trying to do;

It's a old B/W photo that I replaced the original sky with a timelapse sky.
I did copy the sky layer, inverted it, mask it and put the clouds into the ground plane.

The problem is that all the shadows are flat.

pedro



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Cassius Marques
Re: Adding moving clouds shadows to a still panoramic photo / replacing the sky with a timelapse sky/clouds sequence
on Aug 8, 2018 at 12:34:02 pm

[Pedro Luz] "The problem, as expected is that the shadow looks flat on the ground plane of photo, not following the geometry of the ground plane."

Well, its because there is none, right? So if you want it to follow the geometry, you would have to create some geometry. You can project stuff onto geometry in AE, using lights and setting the emission within a 3d layer's material option to 100%. But it's not a workflow that I would recommend.

Displacement maps would be to troublesome too.

If I had to do this, I would bring that reference photo to a 3d app and extrude some shapes there (a lot easier than duplicating planes in AE). You'll still need to match cameras and then decide if you want to render the shadows in the 3d app by importing your rendered sky or bring the geometry back into AE via third parties (E3D for example). So you're able to project and composite it there in a workable manner.

Cassius Marques
http://www.zapfilmes.com


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Pedro Luz
Re: Adding moving clouds shadows to a still panoramic photo / replacing the sky with a timelapse sky/clouds sequence
on Aug 8, 2018 at 1:49:35 pm

Thx for all the info,

I'm trying to avoid a trip to town into 3d, I was wondering if there was some easier way to do it.
A long time ago I did a lot of work in 3d max, I'm familiar with some concepts, but I don't work in 3D for some a long time.

Tried to find some tutorial where I could find camera mapping and or projection mapping regarding 3dmax, I can find some, but I can't really find what I need.

For now I will try the displacement map and cc corner pin and see the results.

If I go to town, my idea would be to mimic the camera view (not easy because is a panoramic) map the timelapse sky into a top plane, create some geometry that mimics the old photo and cast the shadows into the ground plane, rendering only the shadows.
Bring the rendered shadow map to ae and comp into the scene.

Any other ideas, much appreciated.

The photo I provided is for reference only, the one I'm working is much more wider and was done using three pictures.

pedro


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Steve Bentley
Re: Adding moving clouds shadows to a still panoramic photo / replacing the sky with a timelapse sky/clouds sequence
on Aug 8, 2018 at 5:20:59 pm

On a side note: If the image is (as is suggested by the provided pictures) from a book, there will be a dot pattern used in the printing. As soon as you animate anything in the picture it immediately looks fake due to the dot pattern not moving like film grain moves. It screams "postcard". (watch a few bad B movies and you will see this happen frequently)

Depending on the resolution, you can sometimes use clever software to remove the dot pattern but its tricky (do they still make Ofoto?) - the dots are where the detail is; in fact, in printing, get rid of the dots and there isn't much left at all.

Using a grain killer often makes the image soft (and the reference is already soft enough due to age and the de-rez from the printing) plus these filters were designed for removing film grain which has a very different structure to a print half-tone or color sep.



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Pedro Luz
Re: Adding moving clouds shadows to a still panoramic photo / replacing the sky with a timelapse sky/clouds sequence
on Aug 8, 2018 at 6:55:34 pm

Thx for the follow up stephen, no, the picture that I'm working was done in a film scanner at 40k.

Anyway thx for the advice.

Trying to find a tutorial for 3dmax regarding camera mapping, that shows more or less what I need to do.

pedro


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