I’ve noticed that the VFB window doesn’t move smoothly when I’m dragging it around quickly. If I’m moving it slowly, it doesn’t hitch.
Can you illustrate the issue through a video recording?
Yes, you can download the video here (link expires in 7 days): Unique Download Link | WeTransfer You can clearly see that other windows such as the Material Editor move perfectly smoothly. It’s only the VFB that’s stuttering while being dragged around. It’s pretty jarring.
This happens on all workstations here. One of the workstations (the one in the video) has a fresh Windows install with the latest updates and the latest drivers and there’s nothing running in the background that takes CPU or GPU resources. I don’t remember this problem happening with earlier versions of V-Ray.
Do you have a multi-monitor setup? On my end, it seems to stutter only when the VFB window edges go to the other monitors.
On the PC where I recorded the video I have only 1 monitor. The other workstation where the problem also appears has 2 monitors.
Doesn’t happen on my end. Does it happen on a fresh scene?
It does, but it appears to be much less severe. It’s very pronounced in complex scenes though to the point of being a hassle to move the window around.
yeah im getting this too..very stuttery. I cant help feeling im having a lot of driver related issues with vray 6, so many crashes, restarts needed etc, on basic scenes too.
Heres a video of lag
https://drive.google.com/file/d/14MR8S0\_sfR08-1htJahDMwREQ6viuXfI/view?usp=share\_link
I see.
Does the behaviour disappear if the VFB window is dragged AWAY from the Max ui, into empty desktop space?
I have a feeling the issue isn’t with the VFB per se’, but with the need to redraw the non-Qt Max UI.
Could someone with the issue kindly test this?
still lags for me when over empty desktop space.
Same here.
Would you kindly try two different things?
First, close the scene explorer, see if the issue of the glitching persists.
Then, with the scene explorer open, open a Max VFB, and minimise it. See if our VFB drags around as expected.
It feels like a fight for focus bewteen some parts of the Max UI and the VFB, i’ll keep investigating, and keep you posted as soon as we can repro the exact behaviour and file a bug report (i.e. it’s in our powers to fix.).
I found out what triggers this! It has nothing to do with the Scene Explorer. It happens only if the VFB window touches the bottom edge or the right edge of the screen while moving it around. For some reason it doesn’t happen when it touches the top edge or the left edge of the screen. It’s still strange though why only the VFB has this issue. Other Max windows such as the material editor doesn’t lag no matter which edge of the screen it touches while moving it around.
yeah i concur, bottom, left or right, but not top..there is a delay before the lag too 
Nice find.
The VFB is the only Qt window of the ones you mentioned.
Could you verify the two cases i mentioned?
We’re trying on our end, but the reproducibility is sketchy at best, even on different workstations.
I will try. I just need to know what is “Max VFB”. Did you mean the Rendered Frame Window?
I still get the lag with the scene explorer closed and rendered frame window minimised. (see attached video)
vfb_lag.zip (1.63 MB)
Yes, that’s the one.
I still get the lag with the scene explorer closed and rendered frame window minimised. (see attached video)
Argh.
To be clear, our understanding so far is that it’s a fight for focus/redraw between the three (!) different UI APIs co-living inside Max currently.
Scene explorer is .net, most of the rest of the Max windows are winAPI, while the VFB is Qt.
If you have an old V-Ray version, where the materials UI weren’t Qt but winAPI, dragging the compact mat editor around would crawl even on very modern hardware.
Same for the render settings window (the threads on this are many.)
This was initiated by Max, not by us, version over version, and we had to live with it, until we moved to Qt.
There is a very small chance that we’d be able to do things on our side to ameliorate the issue: it comes with transitioning times like the ones we’re in right now, where everyone is migrating to Qt, but not everything can be done at once, and so there’s mixing and matching of *very* old, old, and new.
We’ll keep looking into this, sorry for the bother.
Got it. Well, I tried the steps you mentioned, but it doesn’t seem to make any difference. The VFB still stutters heavily. 
Hello. I was wondering if this issue is still being looked at. It’s been I year and the VFB window still stutters when moved around and it’s really bothersome.