-
Parallel Sunrays in 2.5D|Pseudo3D Scene
Hi,
I’ve seen that the topic of parallel rays has been discussed years ago; however, I can’t seem to apply it to my case. Additionally, perhaps new methods have emerged.
Here, I have built a pseudo 3D scene made of many flat 3D layers (see street_scene img). At the moment, there is panning camera motion. Later, it is planned to add motion of the cars and some animated 2D characters.
Now, I would like to add parallel (volumetric) sun rays that shine from the top left corner, behind the trees. The main problem to solve is that the sun rays should be either on:
– one top-level adjustment layer, which takes into account all the Z-depth information; otherwise, it will break the 3D container.
– several flat layers within the scene itself, also turned into 3D, so they are rendered like everything else.What I have tried so far is generating radial rays, not parallel:
1) CC_Radial_Blur and CC_Light_Burst_2.5 applied to a top layer (see street_lightburst img): These generate flattened versions of the rays, which seem impossible to compose with scene objects located at various depth values. Also, if these are generated from inverted sky alpha, it clearly appears as a 2D overlay as the camera moves. Besides, these methods don’t seem to generate rays that face away from the camera lens and are hard to control as the light position influences the ray length and intensity. Good for anything else, but not this.
2) Trapcode_Shine applied to a top adjustment layer (see street_shine img): Contrary to what was seen in some tutorials, the 3D Light option doesn’t seem to work with pseudo 3D. I was able to fill the scene with light streaks generated from the layers, but these resembled volumetric shadows, inverse to what was possible with the other effects in (1). However, this effect was able to generate some rays even when the light was behind the camera.
In a nutshell, I am looking for a method that would generate a volume of rays and block the ones that are behind the alpha>0 in 3D. At the worst, some sort of method that would at least sample the Z-depth info and generate a number of ray layers, so I can mask them manually.
Any thoughts, ideas, or experiences?
Some contents or functionalities here are not available due to your cookie preferences!This happens because the functionality/content marked as “Google Youtube” uses cookies that you choosed to keep disabled. In order to view this content or use this functionality, please enable cookies: click here to open your cookie preferences.
-
4 Replies
-
You should be able to use a track matte pointing to one layer, which means you would have to precompose the foreground objects, or you could check out the Set Matte effect – applied that to your light rays layer, then point it at your foreground objects.
Set Matte works quite well, but you may run into an issue where the 3D space does not line up with the 2D layer. In which, I’m back to suggesting a precomp. You could use a script like Video Copilot’s 3D Precompose which keeps your camera linked across both comps.
-
Hey,
Thanks for your input, Graham.
If I got your idea correctly, then I’ve already tried that. It gave similar results to what can me seen in Lightburst example image. There – please, correct me, if I’m wrong – the raygen takes the matte from what’s seen in current frame from the camera i.e. skies. The problem arises when layers close to cam begin to intersect those in the background (see in another example street_from-2D-matte attached: traffic light front of bg houses, notice the circled areas), which in motion makes the effect 2D-ish. Besides, the edge also cuts the matte.. I could extend frame upward a little, however, it won’t remove the elephant from the room, as the source has no depth data.
If I use some custom matte instead, then the rays cover all the objects equally, no depth. I could possibly use the depth matte to composite those rays over the scene, yet it won’t generate the shadows from those objects, flat again.
Seeing the examples, can you suggest what am I missing? Or maybe whole another approach?
This far I’ve tried, with Shine on adjustment layer I can generate some sort of radial volumetric shadows rays, not the light rays.
-
I think a big part of the issue is you really don’t see volumtric light that is coming from behind the camera. It needs to be from a side or in front of the camera moving forward.
-
Hey John,
Why would that be a problem?
Actually, as the light’s position went behind the camera, I was unable to generate any ray in any method, even I’d like to do so. Thus, all my example images are light-in-front-of-cam cases, even I am looking for the shots where the light source is off-frame.
Reply to this Discussion! Login or Sign Up