Panoramic Camera Awesome
Posted: Sat Mar 29, 2014 9:14 pm
The Panoramic Camera was a great addition to Octane (can't remember when it came on board). It's amazing how much slower custom lights are relative to their equivalent in an HDR environment. That is especially true if you model things like parabolic reflectors with light blocks for your lights like what you would have in a real-world studio. In that case, all light rays are really INDIRECT light rays, because no light makes its way out into the scene directly, without first bouncing off the light block and reflector.
This is probably old news to many:
I just did a test where I removed everything from the studio...the seamless along with any other things meant to show up in glossy reflections, and "baked" just the three studio lights to an .exr image for my HDRI. So I had just three lights on a black background as a result. Then, in my scene (studio + subject(s)), I removed the three modeled light meshes, and replaced them with the HDRI for my environment and I have to say that my render times are probably roughly 100 times faster as a result. Where you really notice the improvement is in the dark areas where light is so scarce. Using HDR, the moderate to well lit surfaces cleared up in about one hour as well as the dark areas, with specular transparent surfs somewhat longer. When using modeled lights (meshes), I might have to spend 130 hours to render a complex scene and STILL have noise in the shadows and dark areas. But with the HDR equivalent...just one hour, MAAAYYYBE two. The only exception, as indicated above, is with specular surfs with dispersion. They take longer, but STILL, maybe 10 times faster?...I am running a test right now to see.
Since I use the exact same studio setup for all my test renders, I only spent 12 hours building the HDR, which I can now use forever. What is really cool about this, is that that 12 hours is to get a CLEAN, relatively noise free HDR. That is only really necessary when specular and high-gloss surfs reflect the image of those lights. If you do not have to worry about those reflections, you can drop the HDR render time down to practically nothing because the noise in the HDR will not show up on anything.
The only limitation with this idea is that the lighting HDRI cannot have any occluding objects burnt in as well...You have to leave that up to modeled meshes for that, unless it is something simple like a studio lights's light block sitting right in front of the bulb. So if you have recessed ceiling lights for example, you would have to figure out how to integrate the HDRI so that it shines through the recesses.
This is probably old news to many:
I just did a test where I removed everything from the studio...the seamless along with any other things meant to show up in glossy reflections, and "baked" just the three studio lights to an .exr image for my HDRI. So I had just three lights on a black background as a result. Then, in my scene (studio + subject(s)), I removed the three modeled light meshes, and replaced them with the HDRI for my environment and I have to say that my render times are probably roughly 100 times faster as a result. Where you really notice the improvement is in the dark areas where light is so scarce. Using HDR, the moderate to well lit surfaces cleared up in about one hour as well as the dark areas, with specular transparent surfs somewhat longer. When using modeled lights (meshes), I might have to spend 130 hours to render a complex scene and STILL have noise in the shadows and dark areas. But with the HDR equivalent...just one hour, MAAAYYYBE two. The only exception, as indicated above, is with specular surfs with dispersion. They take longer, but STILL, maybe 10 times faster?...I am running a test right now to see.
Since I use the exact same studio setup for all my test renders, I only spent 12 hours building the HDR, which I can now use forever. What is really cool about this, is that that 12 hours is to get a CLEAN, relatively noise free HDR. That is only really necessary when specular and high-gloss surfs reflect the image of those lights. If you do not have to worry about those reflections, you can drop the HDR render time down to practically nothing because the noise in the HDR will not show up on anything.
The only limitation with this idea is that the lighting HDRI cannot have any occluding objects burnt in as well...You have to leave that up to modeled meshes for that, unless it is something simple like a studio lights's light block sitting right in front of the bulb. So if you have recessed ceiling lights for example, you would have to figure out how to integrate the HDRI so that it shines through the recesses.
The error for Monte Carlo sampling is square root which means to halve the error (noise) you would need to take 4 times as many samples.