Hey guys,
Today I wanted to start rendering with the path tracer but my final renderings look so bad that I cant use it.
There is a lot of flickering in the shadow and the glas itself.
All renderings I found with path tracing are so much better quality then mine.
Can somebody help?
No Idea?
My first guess would be, are you using the Denoiser? If so, turn it off and raise the samples. For the best explanaition, watch this video:)
Also, is it intentional, that the part of the glass, that is in front of the table is clear, while the part of the glass statue, that is “above” the table, and has the black background, is blurred? (I guess, it´s depth of field related, and translucent materials don´t work well with depth of field)
The denoiser is used, obviously. That’s what causes the flicker, in the shadow especially.
Path Tracers are really primitive. There’s really not much more you can do than simply increasing the number of samples and waiting longer for each frame.
Hey thank you for your answer! How many samples would you recomend?
As stated in the video, the samples count is something, you have to test for your scene. He starts with 16 spatial and 16 temporal, so try that first, and see, if that already is good enough, or if you need more 
I recently rendered two images, and because those models had some large but rough metal areas, that were indirectly illuminated by emissive surfaces, i raised the samples to a total of 2048 (in 4k). But don´t ask me, if it was 64 spatial and 32 temporal, or 128 spatial and 16 temporal, can´t remember ^.^ Could also be, that i used one for one image, and the other for the second image.
If you want see the results (and i am no pro, so plz forgive the not very good textures and results etc).:
On the first one, you can still see some noise on the smaller Hangar doors at the neck of the Ent-D, so … could have been a little bit more for that area.
This is likely due to fireflies from refractive glass. You can clamp path exposure in the post processing in the “Max path exposure” settings, or you can use the command console command “r.pathtracing.approximatecaustics 1” which would likely help too, although it will make your glass look different. As others have said, increasing samples will help a lot too, but refractive glass is always a bit challenging to render and requires loads of samples, or workarounds as mentioned above.
I use 32 spatial and 32 temporal samples and i’m very happy with it. And i set path tracer with 32 bounces and 2048 samples (no denoiser needed!). Extremely low renders but perfect results.