I just did a render of a ship I modeled. In materials, I used an emmission shader in the engines. However, it has caused some noise to appear. I know this is common when light is close to an object. Is there anyway to keep the effect, yet reduce the noise?
Increase samples.
Use denoising.
Use clamping.
Emission shaders cause more noise (especially really bright fireflies) than using lighting objects like point lights, area lights, etc. It may be better to only have the emission shader visible to the camera and use other forms of lighting to illuminate the meshes.
Also try turning off MIS, as it will compete less with real lighting.
One reason I dislike Cycles is that it produces noise, there should be code already to prevent those sort of things, but unfortunately there will have to be lots of workarounds and hacks to prevent noise and fireflies from hapenning.
Such as mirrors are dangers, glasses also, etc. Shiny surfaces up to a certain degree can pass but once they get intense light casts they end to spit fireflies everywhere.
So for example if you want to use glass, use transparent surface, if you want to use mirrors, use glossy materials instead. Chances are that if you stick only with the Principled shader you will have most of the times proper results. The alternative way is to switch to EEVEE instead and enjoy rendering (with game like graphics) without any technical difficulties.
Some other ideas about noise can be learnt here, so this goes to anyone really interested.
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There is code to prevent noise… in the form of a denoiser, which it does come with already.
The thing is though, as Cycles is mostly an unbiased renderer, code like that is by default disabled to ensure that the renders are as true as you can get with ray-tracing.
Denoising is a good workaround but is a bit lossy. But indeed there is no other way, is mandatory to use it to prevent such mistakes.
However it would be even better if there was a rendering technique to save these things from occuring. Not so much about the noise but most importantly the fireflies. Is like at some point the pixel goes “dumb” and decides to go out of color range instead of just borrowing information from it’s neighbors.
