Hello there, new user here and fairly new Blender user! I hope this is the proper place to post this and please bear with me if I don’t give all of the necessary information. I’ll try to explain my question as best I can!
Recently, I’ve started using cycles to try to render scenes from an indoor perspective. I’ve created a simple blend file with a room and a door, a space outside the door, and a lamp. Inside the lamp there is a UV Sphere with an emission material attached to it. This scene is meant only as a test scene so I can work out settings for cycles and interior scenes and is by no means a final product.
The problem I am running into is fireflies.
I have somewhat mitigated this by setting the direct clamp to 0.8 and the indirect clamp to 0.8 but even at 2000 samples the image still looks blurry and a bit grainy.
Now, I’m still a new user, and I acknowledge that there are techniques for optimizing a mesh for rendering that I’m not yet aware of, but I’ve done my share of google searching and haven’t turned up much, even modifying the render settings still yields a barely acceptable result.
This scene is designed with a dimly lit result in mind, but my question is, how do I avoid fireflies and graininess while still retaining the sharp object edges that I would expect to see in a real life setting?
If someone would be so kind as to look over it and point me in a direction that might be able to help my problem, I would appreciate that so much. I’m trying to build my skill level and google isnt really producing the information I need!
Use a different render engine. Seriously. Large room with small, hidden light sources: That’s a nightmare scenario for an unoptimized pathtracer like Cycles. Period.
Nonetheless, some small tweaking might help…
Your unaltered file, 2000 samples, render time 04:36.41 (yes, my GPU gets old…):
Thank you so much for your reply! The techniques you used to optimize will definitely help in the future! When you say use another rendering engine, what would you recommend for a scene like this? I’m currently running it with the Blender internal engine but I realize that support for that is basically nil at this point. Is there a good, free rendering engine that might work better than cycles for this kind of application?
First of all Cycles is a Path tracer and Path tracers are not the best (if not the worst option) for Interior scenes.
If you understand how a path tracer works then you’ll understand why Cycles is not the tool to go for. As I mentioned in many previous posts and threads Cycles is not capable of solving interior renders unless: You fire up thousands of samples which means you have unlimited time, buy one or two powerful GPUs which means you’ve some money or finaly do mambo jambo tweaks and hope for the best.
Here is a small excerpt from Yafaray’s User Guide about path tracing:
How it works:
Primary rays are shot from the camera (antialiasing samples) and they intersect with the scene [1]. They compute direct lighting and recursive raytracing.
Each intersection averages secondary path samples as well [2], which describe a random path bouncing on diffuse components a number of times (path depth). In each bounce, shadow rays are calculated [3].
Advantanges:
It performs Global Illumination.
Fast in outdoors and Image Based Lighting, because paths find the background easily.
Unbiased, delivers correct results.
Soft indirect lighting if enough sampling.
Disavantages:
Variance shows up as noise.
Lot of rays are needed for caustics.
Inefficient in indoor scenes, when light sources are too hidden, bright or too small.
Doesn't like omni lights (spot, point) and mirror surfaces. Better use area light types and glossy.
Hello @stealthyblue, I gave it a try and changed the light to an area lamp, and deleted the light that was outside the model (I don’t know exactly why, but it has a huge impact on the render times).
Then I changed this parameters into the render settings:
Rendered on CPU took 1:48 to render, but there’s almost no fireflies. There’s obviously too much noise, but it wouldn’t take that much samples to get a clean render.
