When we make a movie of some architecture, we can often see moire flicker on the louvers. Here I will show 2 ways to reduce the flicker noise.
An Example of Moire Flicker
I rendered a movie of buildings with handrail walls by Twinmotion. You can see so much noise!
This is very common trouble in CG, and with this trouble, you will not show what you really want to show bothered by the noise. There are 2 good methods to reduce the noise.
Method ①：Increasing Resolution
This is the simplest way. It is better to reduce the noise that first you render in 4K resolution and then reduce the resolution to Full HD than that you render in default Full HD resolution from the beginning.
Please see the movie below. It is not perfect, but it became better!
You can set the resolution 4K from More > Camera settings > Output size of the Clip. Higher resolution, less noise. If you want 8K resolution, please input values 7680 and 4320 from More (below Output size).
When you convert 4K or 8K movie to Full HD, even if you don’t have Adobe applications, you can use FFmpeg. Please see the previous article. Here it is a command to convert to Full HD.
ffmpeg -i input.mp4 -vf scale=1920:-1 output.mp4
【FFmpeg】静止画を動画に変換する、動画を軽くする(not translated yet)
Method ②：Using Texture
It takes time and effort, but this method can reduce noise more effectively. Replacing balusters (louvers) with a texture image with alpha channel.
In my own way, when I make texture using Photoshop or Illustrator, it becomes easier to work if you interpret “mm” as “px”. In this case, range size of balusters is W2400mm x H1100mm, so first I make an artboard 2400px x 1100px, then make balusters according to the size, and finally set the color of the balusters completely white and export .png file.
Then I make a plane sized 2400mm x 1100mm in SketchUp, and apply the texture. If set the texture size to 2400mm x 1100mm, then the texture will be applied with the perfect size.
After importing to Twinmotion, you can adjust the color of the balusters.
I could remove the noise!
Summary
To reducing moire flicker on the louvers, 2 methods are effective, ①Incresing Resolusion and ②Using Texture. ② can remove the noise more greatly, but if you want to emphasize the solidity of the louvers, you can choose ①. Please select each method according to the case!
That’s all, thank you!
