New to lux need help

witcherask_a3dd58a1c6

I was watching youtube videos on lux render and they were rendering huge secenes in like a minute. I mean in minute image looks clean.
Whereas in my image its been 5hrs and there are whitespots on the scene all over.
Am i doing something wrong.

StratDragon

Depends what you mean by wrong and depends strongly on your CPU and RAM and possibly your GPU if you use that option or can use it.

If you seeing scenes rendering in minutes it could be the GPU enabled rendering that was available in LuxRender as of version 1.0, you need a CUDA equipt Nvidia graphics card which I think started as of series 2xx. Another possibility is it's a render farm meaning a bunch of computers on a network are assisting, which you can do free in LuxRender.

As for white spots you might have the lighting in your scene to intense,. If you are using Studio to light the scene keep in mind most of the Studio lights will give you issues unless you modifiy them or if you're using Reality you can use those lights as they will work "out of the box"

You can adjust the gamma in your scene while it's rendering. For indoor scenes I tend to use the Reinhardt/non-Linear
and just use few lights and make sight adjustments, for outdoor scenes I generally use a Studio distant light and name it "Sun" as my only light source (some use mesh lights for outdoor and swear by them) for this I use the Linear Kernal, Film ISO at 100, Shutter at 1/125 and f-stop at 16. Gamma I set anywhere from about 2.2 to 2.6 and let it run for a few hours even with an quad core i7 and 12 GB RAM, a few hours is normal.

White spots are also more evident in LuxRender version prior to 1.0 and they are refereed to as "fireflies", it can be especially noticeable on overly glossy surfaces with lights intensifying the undesired effect.

witcherask_a3dd58a1c6

Well i already have a i5 with 8gb and nvdia 560ti.
On statistics it shows GPU 200s/p I dont know if i had enabled gpu rendering option though?
I have 1 skylight to 0.2 rest of them are turned off. Lux version is 1.2
My image kinda looks like this. And its been like that with not much change.

Herald of Fire

I mentioned this in another thread about Luxrender, but it's important to look at the following if a scene seems too noisy.

1. How large is the scene you're trying to render. What I mean by this is how far away is the farthest object in the scene from the camera? Yes, include skyboxes in this if you're using any (I strongly recommend you don't use them).

2. Are you using volumetric glass or water anywhere? Anything with 'highly realistic' glass is volumetric and has a huge impact on render times. Water similarly.

3. What are the surface materials like? Most materials won't work immediately well in Lux, and will need tweaking. If your surfaces are too glossy, then it can reflect light all over the place, which makes some very noisy renders.

witcherask_a3dd58a1c6

Well scene is actually very large. I was just rendering part of scene. I mean chars which are out of the screen doesnt impact render times or do they??

I aint using any glass or water in the scene.

I think most materials are set to glossy.
Anyway to reduce noise and make image more clearer

Herald of Fire

It's important to realise that Lux doesn't care what the camera is pointing at from a calculations standpoint. It still calculates everything that isn't in frame, and that means that you're effectively rendering the entire scene, whether visible or not. The reason that Lux get's such realistic results from lighting is because it calculates how light bounces off surfaces in the way that real light does. What this means is that scenery off-camera is still reflecting light into your scene, and is therefore still an integral part of the final calculations.

Unbiased render engines will calculate pretty much everything, regardless of whether the information finally makes it to the camera or not.

witcherask_a3dd58a1c6

So does hiding stuff in your sceene tree works??

Herald of Fire

It does, but bear in mind that if you remove something that would otherwise cast a shadow or have an effect in your scene, then your final render will lack that extra detail. It's always wise to hide elements which aren't directly in view as long as they aren't casting shadows or are needed for reflections and so on. The less geometry and materials that Lux has to calculate, the quicker it will render and the less noise the final image will have.