"Grainy" lighting

[neo0.]

It's hard to see, unless you view the full size version....

[PureSpider]

Yeeeeeees?
And whats your point?!
Why is there not a descriptive thread title again and what's the "it" we're supposed to see?

[neo0.]

Look carefully at the shadows on the spheres.. They aren't soft.. They are very grainy, as the title says..

I switched to MLT.. and with a fraction of the samples, it already looks much better... But still, if you look the little sphere, it still looks alot like highly compressed image..

[StompinTom]

That's a byproduct of just using Bidir and no Metropolis. There is a distinct pattern to the sampling which tends to show up if you haven't rendered it long enough. Render it longer and it will disappear.

[neo0.]

I switched to pure gray instead of greyish-blue and the problem seems to be gone.. Using MLT like before..

[dakiru]

It's hard to see, unless you view the full size version....

Just bake longer. How long did you bake? Or you have a lot of light layers and turned off some of them?

[CTZn]

First, check the saturation of you emitters. Saturation will always amplify noise.

then, when playing with colored emiters you often want to tweak the camera white point. It has also the power to emphasis or dimm targeted colors.

If you find metropolis better for this purpose then go for it, myself could hardly do without and we have the choice for a reason.

Finally, noise is the definition an unconverged render, damnit neo0. you are beating yourself here.

[neo0.]

CTZN, thank you for the hints. I'll look into it. I realize that what I was talking about just sounds like noise.. but it didn't look like noise.. It looked like what happens when you are saving a pic in some image editing program and you turn the quality waaayy down.

Here is a screenshot of my scene

This is exactly why I would really appreciate the ability to recolor our materials directly in indigo.. Going back and forth just to tweak colors can be very time consuming.. Heck, many renderers let you change the material type in real time, and all I want is just to be able to change the color.

[Stromberg]

Well it's saved in jpg, so that it would be jpg artifacts you are seeing could be true...
I think it is just noise aswell. but try and save it in other formats and see if it goes away.

And many render engines dont let you change the materials on the fly, it's mostly SWAP from fryrender who does that.

[CTZn]

I realize that what I was talking about just sounds like noise.. but it didn't look like noise.. It looked like what happens when you are saving a pic in some image editing program and you turn the quality waaayy down.

StompinTom exposed the cause, bidir alone uses a quasi random sampling distribution. It is more efficient than pure random distribution by avoiding clusters/gaps of samples) but obviously creates a pattern when samples count is too low.

[lycium]

a pattern when samples count is too low.

quoted for truth

[pixie]

StompinTom exposed the cause, bidir alone uses a quasi random sampling distribution. It is more efficient than pure random distribution by avoiding clusters/gaps of samples) but obviously creates a pattern when samples count is too low.

There's some examples posted before where this pattern persists even after lots of sampling.

[CTZn]

I remember this pixie. I couldn't find a related report, can't tell wether it was fixed or not.

Lycium: I removed the 'do'h' before posting is that to say that the rest is bullpack ? I'm just asking to learn more, pardon the weird way.

[lycium]

yup, sometimes there are patterns in the image even after many samples per pixel; it depends on the complexity of the scene.

ctzn: no problem at all with what you said, i quoted that part because it nicely sums up most of this thread, all the images...

one more thing about the images: neo0 usually posts large png files, which are lossless and would be ideal for demonstrating noise; however in this thread he uses strongly compressed jpeg files, which tend to change monte carlo noise into mushy jpeg artifacts. it should not be surprising then that there are jpeg artifacts, not to be confused with MLT splat patterns!