big scene handling

Corona Corona for 3ds Max Issues
1

I have a pretty big file of a city here. (~ 28 million polys). Simple setup with an override material & sun/sky.
In IR the performance drops significantly, to the point where its not really useable anymore. (see corona_ir.mkv).
Normal Render performance is fine again as you can see in the screenshot.

In Vray IR performs with no issues.

corona_ir.mkv (5.68 MB)
vray_ir.mkv (13 MB)

corona_normal_render.jpg
corona_normal_render.jpg1505×759 364 KB

2

Again no bug :] but the way Corona IR uses Embree: In order to run/start the scene in IR quickly, different modes/flags are used for production and interactive rendering. I’m working regularly with geometry like that (no instances, unique geo, large scale meshes) and also want to see some more flexibility here. Someday I’m going to request at least Corona string options to be able to adjust that behavior for certain scenes. I would gladly trade preparation time and/or memory for IR speed in such scenes.

Good Luck

3

I thought it would be something along the way…did not know where else to post it.
Anyways, thanks for the information! This means that in scenes like that IR is not really an option as of now?

4

WOW that’s a big difference! i guess that a scene for the developers would be handy

5

Hi,

We’d very much like to take a look at your scene and see if we can somehow improve this.

Would you be able to send your scene to us? Instructions on how to do this can be found in my signature.

Cheers,

Rowan

6

We have to live with that drawback it seems as there is no way to change Embree behavior currently. You can of course try to optimize the geometry somehow.

Indeed! My worst ratio was about 1:3 :smiley: Let’s see if Rowan can find something useful here…

Good Luck

7

I uploaded the file via dropbox. The name is city.7z. I hope 7zip is ok.

8

Hi,

Thanks I have the file. I will take a look and let you know when I have some more information.

Cheers,

Rowan

(Report ID=CRMAX-278)

9

I’ve noticed a similar thing, although I mostly deal with highly detailed interiors with high res materials. Once scenes start becoming more complex and detailed the interactive viewpoint slows to the point of becoming unusable.

10

Could it be that material override contributes to this?
I’ve noticed that when using it, any scenes with a large number of objects will be slow in IR, as if the material override is parsed/re-parsed more often than it should.

11

I tried without, but it did not make a difference in this scene.

12

@clement_st

What is the specification of your computer?

Thanks,

Rowan

13

dual xeon e5 2690v3, 64GB Ram, Quadro RTX4000

14

Thanks for the info.

I have been able to reproduce it here, it is with our dev team to see if we can do something about it :smiley:

Cheers,

Rowan

15

thank you!

16

I just ran into the same issue with a different scene.
This time the poly count is lower (~ 10 million polys) so the IR slowdown is not as obvious, but we are still talking about an almost 50% performance loss as opposed to the “normal” render. 3,6 vs 6,6 Rays/s total.
I guess Frood already identified the problem and I hope there will be a solution for this.