Within VFX, I have been working on changing the sky so that it will look part of different scenes. The image that I started was in daytime with a standard blue sky. I had to learn how to change it to make it look like the scene was in the nighttime. The images below are my end result of the sky changing effects although changing the sky from daytime to nighttime like this or from a standard sky to an apocalyptic style sky like the second image is rather different. The style used to create the nighttime sky retains some of the blue from the original sky as you may be able to see with the outline of the trees or the top half of the sky is slightly blue. Whereas the second image doesn’t have any blue in it what so ever.
First of all I needed to duplicate the footage with Ctrl+D then place the sky image that I was using in the center of them. Then I had to add a linear wipe to my sky layer with the transition set to 30% and wipe angle at 0. The eye icon on the left side of the name layer then needed to be unchecked on the top layer so that the sky would be visible for me to be able to put the sky where I wanted it as well as scale it to match how far I wanted it to go. To top this part off, click and drag the numbers on the “Feather” option to feather it to your desired amount.
Turn the eye icon back on and add a linear colour key to the top footage. In the “Key Colour” option, select the colour in order to colour pick the sky. Finally, change the tolerance and softness as needed to try to make the sky look as natural as possible.
The second image was more complicated than the first since there was a lot more steps required so that I wouldn’t have the blue maintained in the sky.
This time you need to duplicate the footage of the environment you are using so that there are three versions. There are three little icons on the bottom left corner of the screen, make sure that they are all turned blue so that you have all the options up for each layer. Click on arrows next to the word “None” underneath where it says “TrackMat” and change it to “Luma Inverted Matte”. Pre-compose the top layer then open it up the new pre-comp.
Find “Colorama” in the “Effects & Presets” on the right and drag it onto the top layer. Change the colour option to “Ramp Grey”. Right clicking on the circle will create a black arrow, you need to do this and right click again to make a white arrow. Move the arrows to make a black and white matte, make sure that the sky is completely white with the other objects being completely black.
Next, you need to create a new black solid. Uncheck the and have the black solid layer selected. Select the pen tool to draw over any white marks that remain on areas such as grass that may have maintained them. Turn the eye back on so that the black solid is visible and return to the original comp. Make sure that the icon left of where it says “Active Camera” is blue and uncheck the eyes for the top and bottom layers.
Place the sky where you want it to be and adjust it to fit as you please. Set the opacity to around 70% and turn the bottom layer back on. Pre-compose the top two layers, this allows you to add effects to them. Add a “Matte Choker” which can be found in the “Effects & Presets” (if needed) to the pre-comp to smooth the edges.
I am rather happy with the end results of my work, I feel that the sky looks like it works and way that I edited to colours on the last two works well for the scene and looks rather realistic (in my views). Rather unsure on what I could improve on but I will still need practice as these are my first three tries at making them.