Basic displacement question (very slow render)

[justavisitor]

I'm experimenting a bit with displacement.

The results are really interesting - but is displacement rendering supposed to be extremely slow compared to particles rendering, for instance?

The simple sphere/displacement image in the screenshot takes 4-5 times longer to render than a complex 1GB scene with a lot of hair systems.

[justavisitor]

OK, it turns out that Displacement, Path Tracing and Specular Material is an extremely demanding combination (and for some reason much more demanding than in Particles rendering).

Direct Light combined with a Diffuse shader, on the other hand, cuts render times down to a manageable level.

And it still looks really great.

EDIT: Please see my post below for a more correct description of what I did wrong.

[simdal]

hello, if you want I can do a test. if you send me the file I tell you how long it takes on my system.
hello, simdal

[justavisitor]

Hi Simdal,
That's very kind of you, but I now know exactly what made the scene so heavy:

Contrary to what I mentioned in my previous post, it was not only the combination of a Specular Material and Path Tracing. What really took time was the fact that Transmission was turned up to 1.

When I turned Transmission down, render times also went dramatically down, to about 1/20.

And the image I used was also particularly demanding when Height was turned up to about 15.000, because it almost made the structure look like hair.

So, all in all, it was a series of beginner mistakes...

And Displacement is really amazing.

[simdal]

Well, then good job. if you need I'm available. hello

[justavisitor]

Well, then good job. if you need I'm available. hello

Thank you very much!