V-Ray 3.40.03 - Embree slowdown

[katho3d]

Hello Vlado, I´ve noticed a massive slowdown in some scenes when "Use Embree" is checked.
Here is the rendertime difference in the testscene I´ve mailed to you:

83 sec - with Embree
13 sec - without Embree

Workstation:

Dual Xeon X5680
64GB RAM
Geforce 970

Thanks, Thomas

[vlado]

It looks like your model has a lot of overlapping faces, which are slowing down Embree. If you clean up your model, it will be faster.

Best regards,
Vlado

[katho3d]

Thanks Vlado, I think the overlapping faces are because of the applied noise modifier (confidential data). There are many faces close to each other but they should not overlap. Or at least just a few.
The difference in rendertimes is the same, with or without noise modifier. I´ve also tried to select all overlapping faces and delete them, same result.

[matanov]

There is no noise modifier in the scene that you sent. The count of the overlapped faces that I get is 27177, can you confirm ?

[katho3d]

Hello Peter, of course the noise modifier is applied before I collapsed the mesh Because we don´t have the permission to give the original object to third parties.
And you are right, with the default tolerance setting (0,01) of xView I also get 27177 overlapping faces. You have to set the tolerance to 0,001 or lower. Because the scene units are set to meters and 0,01 means 1 centimeter.
I´ve already tried to cleanup the mesh so there are no overlapping faces, but the rendertime with embree is still much higher.
To show this I´ve sent you a new scene via e-mail (Vlado), with just a few overlapping faces, you can delete them for test purpose but you will get the same slowdown with embree.

[matanov]

Ok, thanks.