My LuxBlend renders are always really noisy or have white spots, no matter how high i put the settings. Do I just need to wait longer for it to render? Sometimes I leave the renders for hours and it seems like it hasn’t progressed at all in render quality
The longer it renders, the better it will look. What sampler and integrator are you using? Have you tried using the newest RC? http://www.luxrender.net/forum/viewtopic.php?f=30&t=2576&st=0&sk=t&sd=a&sid=0464b1a0a5ec2bcf5a2bf86464cba270
I have v0.6 RC5, the latest one. It might have to to with the fact I’m on a Macbook, but YafaRay renders a heck of a lot faster than this - It seems like once the render reaches a certain point it stops becoming less noisy. I’ve checked the logs though, it says it’s still rendering
Yafaray renders faster because it’s a biased renderer. Luxrender is unbiased, so it will take much longer to produce an image with an acceptable noise amount. At the beginning, it’s easy to see the changes, but after a while, it won’t be as easy to see.
You can remove a lot of the noise with Photoshop.
That reminds me, the Luxrender GUI can remove noise.
It really comes down to playing with the render methods. I have discovered that if you “bottom-out” the Metropolis sampler, you can get a speed increase and less fireflies (actually none). Click the Advanced button for Metropolis. Set Mutation to 0,1, max rejects to 10 and intsamples to 1. Then use a bidirectional integrator (advanced button also pressed) with eyedepth to 5 and light depth to 5.
Another approach to “clean” renders with Lux is to use a lowdiscrepancy sampler (with hilbert) with the distributed path integrator. At this point, you can control how many samples occur for the various ray interaction types (diffuse, glossy, specular, refract and reflect).
I have found that if you use the lowest Lux draft setting of direct lighting, Lux renders just as fast as the Blender Internal. Especially if you have glossy reflections turned on in Blender. But you get all the added benefits, less the Blender Internal Renderer bugs, that Lux has to offer, such as real reflections, and mesh objects as lights, true DOF.
IES Profiles are important for reducing noise in renders, especially if you are using the standard Blender lights, and have not taken the time to create mesh based lights. The reason for this is that a Blender light is essentially a single point in space, while a mesh light occupies an area. Because all the rays cast from the same location, there is less variation, hence more noise, and they often hit the same spot, more fireflies. The IES profiles actually spread the light out based upon real light manufacturer specifications.
Get some IES Profiles here:
http://www.hewilliams.com/catalog.asp?company=williams&tab=industrial
Also - with all unbiased renderers you should try and set exit portals and make your surfaces less than 100% bright, eg white should be 0.8 0.8 0.8, to prevent too many reflections that’ll slow down your render.