Hi team, I’m working on a job that involves recreating the sun and I’m wondering if any of you might have some insight on such a task.
The gag is that as the sunsets over the ocean horizon it suddenly flies back up into the sky and starts being hit around like a tennis ball.
The plates have been shot during the day but with no sun visible directly in the frame. We aren’t going for a full on photo real 3d light fest of the sun physically moving across the sky (no budget for that), more of a representation of light moving through the scene (fix it in post 2d styles!).
My initial tests so far are animating a sphere in action with a material node added and pumping up the diffuse values there. Then adding Stingray Bloom, Reflections and Physical Glare as Camera FX.
Couple of questions:
I’ll be working on graded plates (Rec709) but I’m wondering about working in a different colourspace to try and approximate some real light values (above 1.0). Does anyone have any guidance on that? I’m guessing acesCG might be the go? My understanding is that as the sun flies across the sky the motion blur should create more of a streaking effect rather than something clipped at 1.0 white which will fade off to grey in the motion blur.
Also, a lot of this takes place over the ocean so I’m going to be doing some cheated 2d reflections on the water surface. I’m currently displacing a frame of black with some noise and using Stingray Reflections. Any thoughts, gotchas or words of wisdom greatly appreciated!
I did this once (quite a while ago) and I ended up using a Lensflare as the sun for pretty much everything. It was easily moveable around the frame (and you could copy and paste tracking data into the animation channels), plus you got the added bonus of lensflare elements animating around the screen as it moved.
I can’t remember exactly which lens flare it was but probably a Sapphire one with Sun in the name!
I would certainly do this in a sceneLinear colourspace like ACEScg. The reason for this is tone mapping . When you are building up glows, flares and bloom you don’t want to keep banging your head on the upper clipping level. ACEScg has great tone mapping so the roll off on your highlights keeps those values from clipping.
This excellent tonemapping can be a problem when trying to generate clipping like your sun or neon tubes. You will need to pump a lot of exposure into the core
The other advantace to doing the comp in sceneLinear is that your motion blur will behave more naturally. With light in your scene having more accurate values to what the camera would capture, a lot of the stuff like glow and blur will come more naturally. eg. if you have a sun object that has a pixel value of 64, it will be dominant and not get thin when blurred due to motion
Although this is a graded plate we can still cheat this image. Not ideal but use an inverse ViewTransform:
Yes some of your values might get a little whacky. I like to use the example of a white linen suit (The Man from Del Monte). The white suit might get values closer to a light source, depending on how your grade looks.
But don’t worry too much, you will be reverting back to rec.709 but you will get all of the benefit from working in sceneLinear.
