Moving VDB volume in interactive very slow + bounding box visible

Corona Corona for 3ds Max Issues
1

Nothing to explain here - moving vdb or changing settings very slow, looks like reload each time

And the problem with the visible bounding box still here - with global volume or inside/intersecting with another object with volume mtl.

2

Hi,

Some more explanation would be useful :wink:

Are you able to send the VDB in question to us? If possible in a simplified scene which shows the issue with slowness.

The second issue we are aware of and have it logged in our system.

Rowan

(Internal ID=594075946)
(Report ID=CRMAX-264)

3

I thought it was pretty simple, but ok

I have cloud VDB loaded in corona volumegrid, it takes some time to start IR. After that I can move/rotate the camera and everything runs smoothly. But if I try to change the position/rotation/scale of corona volumegrid during IR it takes a lot of time. Same if I try to change some settings like scattering or absorption.

Just checked - 7 seconds for a particular VDB file. So if I try to move it or change the scattering scale I have to wait 7 seconds each time. And max is locked during those 7 seconds.

I can send VDB but I see no reason for that - it behaves the same with any VDB. The bigger grid (amount of cells) - the bigger lag.

Checked with Pixar cloud (I think you have it) - wdas_cloud_sixteenth.vdb runs smoothly, wdas_cloud_eighth.vdb a bit slower, lag is quite visible on wdas_cloud_quarter.vdb, wdas_cloud_half.vdb - 5 seconds to refresh IR, wdas_cloud.vdb - 13 seconds.

4

Hey,

I have some good news, we’ve managed to fix this in v7 and it will be in the next daily build.

The other issue you reported we are still investigating and I will get back to you when there is some more information.

Cheers,

Rowan

5

Bounding box issue fixed: https://forum.corona-renderer.com/ Corona Renderer 7 for 3ds Max - Daily Builds Changelog #msg182024 :smiley:

6

Hi,

I just checked out those Pixar cloud VDBs.

I guess it is to be expected that the larger VDBs take longer to reparse, “wdas_cloud_sixteenth.vdb” is a 1.5mb file, so it would be expected that Corona can reparse this quickly. However wdas_cloud.vdb is a 2.8gb file, so I think it is also expected that Corona takes longer to reparse this file when it is being moved in the IR.

There is always room for optimization, but I think this behaviour can be expected.

Cheers,

Rowan

7

Hi Rowan,

I don’t know how corona working but should it be reparsed each time I move it or change scattering settings? Why this not happens with geometry in the scene. For me it looks like something I wrote about in the first post - looks like vdb loaded from disk each time I move it during IR.

Anyway, I checked it with arnold active shade and everything works fine. wdas_cloud.vdb - instant response to moving volume instead of waiting 13 seconds with locked max.

So probably that’s not something to be expected.

8

Hi,

I’ve done some further investigation and spoken with our devs, even with geometry it looks like we re-parse it with every change.

I checked the same VDB with V-Ray and the behaviour is the same.

I will update the report we have and see if there is some way this can be optimised.

Rowan

9

I noticed the re-parsing earlier when working with bigger VDB files. Would be great If this could be optimized somehow.