I’ve been following a tutorial on atmospheric effects ( sunrays and lens glare) and it has worked well. I now want to apply the effects to a different scene, which is much larger and too much for my PC to render as a single layer. I have had to render out in layers. I have one layer which contains no objects, which is used to render the background HDRI, the others have objects - three layers of trees, one with a road and the other with a car. Question is, which layer do I choose to include the various passes (mist, vector, object and material index, shadow and AO) used in the tut to enable the effects?
Well, first of all, “don’t get me started about lens-flare.” (I worked with a magazine whose photo editors scrupulously studied every (4x5 sheet-film) image for evidence of flare, and who, in almost every case, summarily discarded every film that showed it. “Lens flare” produces white areas that are very difficult to print, and so if your standards of photographic print-rendering are very high, the image becomes technically unusable.)
Having now “vented” this point … … there are basically two ways that the presence of this light are going to affect the underlying image: (1) Hue, and (2) Saturation. Where the lens-flare is present, anything behind the flare is going to be both de-saturated and “tinted.” (It will not be “Alpha.” Light on the glass is not the same as dust on the glass.)
In your compositing setup, the lens-flare areas should be, say, a simple black-and-white image. Use an RGB node to produce a “color of your choice” for the light beam, and use the image as a source of AlphaOver against an image-channel that has reduced hue and saturation. (Or, use the image to directly control the amount of H&S modification that is applied.) Use a “bulls-eye” modifier if you want to simulate the prismatic effects of a lens that is being abused in this way . . .
But, again, seriously consider whether you want to do this. “Lens flare,” to me, is visual pastiche … a hackneyed visual “trope” and a photographer’s error. “Every time I see it, I can almost hear the cicadas in the background . . .” :rolleyes:
… there are basically two ways that the presence of this light are going to affect the underlying image: (1) Hue, and (2) Saturation. Where the lens-flare is present, anything behind the flare is going to be both de-saturated and “tinted.” (It will not be “Alpha.” Light on the glass is not the same as dust on the glass.)