Finishing this little study on why so much firefly in my scene, I realized that the main villain is the material I created, the program gets lost and bursts the pixels.
I rendered only using HDRI lighting and ran out of firefly:
Using only the Sun lamp you can see the problem (even with Caustic off) and in the render decomposition it is possible to see that all the indirect channels contribute to the fireflys (in this image I reduced the resolution, so they will not be so visible):
The normal rendering with 250 samples and the magic of denoise (the first time I use it), with the same 250 samples:
And finally, render with the floor with neutral material and then the objects with neutral material:
- this kind of material is complex and generates many rays, which raises the need for samples to have a result without many adjustments;
- the denoise is magical;
- I need to study more about materials.
Sorry for the long post but I wanted to record my difficulty ... I'm still going forward, but if you have a hint on how to use the node light path to slow down those fireflys tell me!
Here's the solution using brute force (2048 samples, resolution double, clamp indirect and denoise), spending 1 hour and 18 minutes: