Changes to layered materials with absorption in 1.6?

[Dippndots]

I've noticed a really significant slowdown when rendering a layered material with a refractive/absorbing material as a base (sea water with foam in this case). I wasn't aware anything changed here? What can I do?

[maru]

Hi, can you show some comparison of this? Or an example material setup.
Also, the slowdown is compared to which version? 1.5?

[Dippndots]

Hey Maru, I've attached a simplified sample scene below. It's specifically using distance tex. You can see from the screen grabs of the VFB that 1.5.2 is monumentally faster than 1.6 in this case.

[maru]

Sorry for the delay. I have just checked this, but honestly I have no idea what is going on. It could be related to t he way the distance map is handled (maybe?).

One thing is that I was not able to get such huge difference between 1.5 hf2 and 1.6 hf1.

Another thing is that the renders come out completely different, and I did not change anything in the provided file.

[Dippndots]

Weird, I will try doing a fresh install of corona 1.6.1. on Monday and see if that changes anything. I had previously just copied the unpacked 1.5.2 files and then copied 1.6 back on top of them.

Not sure why the provided file would render differently :(

[Dippndots]

I still have the big disparity in render time between using a layered and non-layered material in a fresh install of 1.6.1. Not to mention I'm using a new CPU and Motherboard :(

I've updated the sample file, using the Sea Layered and the Sea Simple respectively should give you similar results hopefully.

EDIT: Updated the max file as there were some hidden items that were probably throwing up missing texture errors.

[Ondra]

CPU and motherboard is definitely unrelated. it is probably a problem in determining which medium you are inside

[Dippndots]

Sooo, there's hope for a fix by 1.7? :)

[maru]

Ok, the new scene works fine for me - I am able to reproduce the issue.
Here are some extra findings:
1) Keeping the layered material applied, but just unplugging the layer 1 material makes rendering fast again
2) Keeping the original layered material setup, but just unplugging the bump map from the base material makes rendering fast again
This is very strange and probably worth looking into.

[Dippndots]

Interesting about the bump, I hadn't tried that combination. The noises in that bump map are animated, perhaps related? (out of the office today and can't test)