<p>It's doable, so long as you have some time, diddling around in After Effects with the Keylight chromakey and the camera tracker... Here's an example I made a while back at 4m25,5m17, 
6m04, 8m33 (and a few other sections): <div class="youtube-embed"><div>
                <iframe width="640px" height="395px" src="https://www.youtube.com/embed/AiVGeoJsAtQ?start=265"></iframe>
            </div></div></p>

CC BY-SA 4.0
2020-05-25T16:38:55.233Z
Ye, this looks like the same method used to mark imaginary lines on a football field.
Justintimeforfun
CC BY-SA 4.0
2020-05-26T08:58:10.403Z
I should add - a bit of key-framed masking and possibly a little rotoscoping was also used to improve the overall key effect in some of the shots
tomh
CC BY-SA 4.0
2020-05-28T22:04:05.140Z
Would this work in a horizontal setup? In the example the image is looking down at the grass. Ideally, in my picture the grass, also works as a back drop.
Justintimeforfun
CC BY-SA 4.0
2020-05-29T05:04:33.103Z
So, while you *can*,  use grass as a greenscreen, it won't make a *good* greenscreen.  The idea with a greenscreen is to get the screen to be as uniform as possible; ideally, the whole screen would have the exact same color value at every point, and ALSO, the talent would be placed as far away from the screen as possible, to keep green light from "spilling" onto their skin/hair/clothes,etc.  Standing on your screen makes this difficult.  Don't expect one-click results if you use grass, and expect to do a lot of rotoscoping and cleanup.  Pro screen lighting gets you closer, initially.
Jason Conrad
CC BY-SA 4.0
2020-05-30T05:05:15.043Z
@JasonConrad what if I used a program to make it usable. I added a 2nd picture for an example.
Justintimeforfun
CC BY-SA 4.0
2020-05-30T10:08:44.433Z
Whatever operation you’re applying to the green field would also get applied to whatever’s standing in front of it, reducing the contrast in it as well, and giving you no better results. There’s a reason Hollywood converged on the solution they did.  If you don’t have the Hollywood budget, I’d recommend a can of green paint and a sheet of drywall. Try the field, too though, just to see the difference for yourself. It won’t be long before machine learning makes all of this obsolete anyway, but it’s good to know where film techniques came from to understand where they’re going next.
Jason Conrad
CC BY-SA 4.0
2020-06-01T21:59:55.220Z
https://www.youtube.com/watch?v=sTe_-YOccdM
Jason Conrad
CC BY-SA 4.0
2020-06-02T07:00:50.090Z
Jason did you manage to get that Colab sheet to work, based on that YouTube video? If you did I have a question for you! https://video.stackexchange.com/q/30275/4426
tomh
CC BY-SA 4.0
2020-05-24T16:44:52.720Z
2020-05-24T16:44:52.720Z
tomh
<p><a href="https://i.sstatic.net/etdZy.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/etdZy.jpg" alt="enter image description here"></a></p>

<p>This is a picture of a green field that changes into a hill.</p>

<p>The idea is can you can have a large, organic 3D green-screen this way?</p>

<p><a href="https://i.sstatic.net/HKmR0.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/HKmR0.jpg" alt="enter image description here"></a></p>

<p>I used a program to normalize the darker green areas of the field using replace color and increasing the thresh hold without losing texture and wonder if this could be done to a live feed?</p>

<3d><greenscreen>
Would a large grass field make a good green screen?
Justintimeforfun
# Would a large grass field make a good green screen?

(Asked by: username_0 on 2020-05-24)

[![enter image description here](https://i.sstatic.net/etdZy.jpg)](https://i.sstatic.net/etdZy.jpg)

This is a picture of a green field that changes into a hill.

The idea is can you can have a large, organic 3D green-screen this way?

[![enter image description here](https://i.sstatic.net/HKmR0.jpg)](https://i.sstatic.net/HKmR0.jpg)

I used a program to normalize the darker green areas of the field using replace color and increasing the thresh hold without losing texture and wonder if this could be done to a live feed?

**Tags:** 3d, greenscreen


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## 1 answers

### Answer by username_1 on 2020-05-24. Score: 1 | Accepted answer

It's doable, so long as you have some time, diddling around in After Effects with the Keylight chromakey and the camera tracker... Here's an example I made a while back at 4m25,5m17,
6m04, 8m33 (and a few other sections):

> **Comments:**
> **username_0**: Ye, this looks like the same method used to mark imaginary lines on a football field.  
> **username_1**: I should add - a bit of key-framed masking and possibly a little rotoscoping was also used to improve the overall key effect in some of the shots  
> **username_0**: Would this work in a horizontal setup? In the example the image is looking down at the grass. Ideally, in my picture the grass, also works as a back drop.  
> **username_2**: So, while you *can*,  use grass as a greenscreen, it won't make a *good* greenscreen.  The idea with a greenscreen is to get the screen to be as uniform as possible; ideally, the whole screen would have the exact same color value at every point, and ALSO, the talent would be placed as far away from the screen as possible, to keep green light from "spilling" onto their skin/hair/clothes,etc.  Standing on your screen makes this difficult.  Don't expect one-click results if you use grass, and expect to do a lot of rotoscoping and cleanup.  Pro screen lighting gets you closer, initially.  
> **username_0**: @JasonConrad what if I used a program to make it usable. I added a 2nd picture for an example.  
> **username_2**: Whatever operation you’re applying to the green field would also get applied to whatever’s standing in front of it, reducing the contrast in it as well, and giving you no better results. There’s a reason Hollywood converged on the solution they did.  If you don’t have the Hollywood budget, I’d recommend a can of green paint and a sheet of drywall. Try the field, too though, just to see the difference for yourself. It won’t be long before machine learning makes all of this obsolete anyway, but it’s good to know where film techniques came from to understand where they’re going next.  
> **username_2**: https://www.youtube.com/watch?v=sTe_-YOccdM  
> **username_1**: Jason did you manage to get that Colab sheet to work, based on that YouTube video? If you did I have a question for you! https://video.stackexchange.com/q/30275/4426  

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