3ds Max UI very sluggish when IPR Is running

[Alex_M]

Hi,

The UI of 3ds Max becomes very sluggish when IPR is running even on a very fast machine like the one in my signature. This is especially frustrating when working on materials with IPR on. I've noticed that 3ds Max uses CPU threads 0 an 1 for UI. Is it possible that when IPR is running on all threads, including 0 and 1, Max has to fight for resources with Vray on these two threads so the UI becomes slow? Is it possible to add an option to exclude threads 0 and 1 when IPR is running?

[3d-laboratory]

I didn´1 have this problem with AMD Ryzen 9 5900x and Quadro P5000 but as I have the general problem of a slow GUI regarding SME and Render setup window Lele (Senior member) wrote in a post , that you should manage your threads so that the first core is only reserved for 3dsMAX. Yesterday I found, that the the monitor management software DisplayFusion also is a cause for slugishness of MAX´s dialog windows. Do you use it by chance? I have two other problems with the VFB- If I do IPR there and hit render MAX sometimes doesnt react anymore. The other thing is that during IPR is running the AutoBack feature of MAX doesn´t work.
Just now Ifound an article regarding that topic in the Autodesk forum which I didn´t know so far:
https://knowledge.autodesk.com/suppo...core-CPUs.html

[Alex_M]

Sorry for the late reply. So how how do I fix this? Using IPR to create and adjust materials is a nightmare on my state of the art workstation using the latest 3ds Max and Vray.
You mentioned something that Lele suggested. Where do I find this suggestion?

[^Lele^]

The suggestion to use Prio was for something else (the whole 3dsmax.exe process.).
As IPR is inside that process, there's no way to manually tweak the cores usage.

I don't, however, get any slowdowns at all when IPR is running (on a single 1900X machine).
Does it happen on any scene, for you, or just with specific ones?

[Alex_M]

Thanks for chiming in, ^Lele^ Yes, this happens in any scene, mostly bigger ones. Very simple ones don't seem to suffer much from this. The slowdown is related only to interacting with materials in Slate material editor. I'm not talking about the 3D viewports.

I'm pretty sure the issue is due to the fact that 3ds Max'es UI uses threads 0 and 1 for the UI and since IPR uses all CPU threads, the UI has to fight with IPR for resources. Is there really nothing that can be done about this issue? This is really driving me nuts. Doing lookdev is a constant pain.

[Vizioen]

I have the same on a very simple material testing scene, it takes 2 seconds in slate to go from one node to the other and load the UI. With a 3970x threadripper and 128 GB RAM.

[^Lele^]

I do not get any significant slowdowns *anywhere* in max when IPR is running.

When old-style UIs are at play, there are minor slowdowns (Perhaps 20% more redraw time as IPR is running.), but that is currently unavoidable (it's on the UI redraw and myriad background calls that take place with those controls, not IPR as such.).
What slowdown i see for us (bear in mind i have not timed it exactly.) is actually lower than that of Corona under the same circumstances (same scene and shaders, under slate), so it doesn't look like it's us doing things horribly wrong.

It could well be the issue is much more pronounced with many-cored machines, where the base clock is (much) lower, and boosting doesn't happen because of thermals, as IPR taxes the CPU as a whole (my CPU runs flat at 3.8ghz on all cores, no boost.).

My guess is that this will all go away as we complete the transition to Qt.

I'll poke the devs about this, but we'd need something that runs materially too slow to figure things out.
If you have relevant scenes, and exact methods to repro the slowdowns, please share.

[Muhammed_Hamed]

This behavior is specific to some of the newer threadrippers, the 2990wx is worst from what I have seen.. and this lag is present on the 3970X in a similar way but not as bad

Take a look at this(happens with Corona IPR as well, this is not specific to Vray)
https://www.dropbox.com/s/cfbt9s60j6...36-52.mp4?dl=0
It is only better when you go to settings and setup IPR rendering threads to something like 50-55

I don't get this lag on my 3990X. I have PBO off and a manual OC/Voltage in place, I'm not sure if this helped in my case or not

My guess is that this will all go away as we complete the transition to Qt.

Awesome!

[^Lele^]

You can see horrible UI lag without V-Ray at play, use scanline as renderer and open an old Raytrace material (in the scanline section) in the compact material editor.
Try and drag the material editor window around.
Now switch the material UI displayed to the new QT-based Phisical Material, and drag again.
The difference is all in leanness of background signalling.

My *assumption* is that this behavior worsens on the mentioned CPUs, and when IPR uses more infrastructure (i *assume* it's got to do with crowding of the data pipes, more than with core usage per se'.) Max caves in.

The difference should be testable for those with the lag, simply by "simulating" a look dev session with QT-based UIs.
It should be even more visible a difference with the slate material editor as that calls an UI rebuild each time the node is selected.
If there is no change, then perhaps something else is afoot.

[Alex_M]

This behavior is specific to some of the newer threadrippers, the 2990wx is worst from what I have seen.. and this lag is present on the 3970X in a similar way but not as bad

Take a look at this(happens with Corona IPR as well, this is not specific to Vray)
https://www.dropbox.com/s/cfbt9s60j6...36-52.mp4?dl=0
It is only better when you go to settings and setup IPR rendering threads to something like 50-55

I don't get this lag on my 3990X. I have PBO off and a manual OC/Voltage in place, I'm not sure if this helped in my case or not



Awesome!

Thanks for the input. How do I set the number of IPR rendering threads? Or is this feature only available in Corona? I'm really stunned that such a terrible UI experience can exist in 2021. 3ds Max probably has one of the worst UI of any software I've used in terms of interactivity.

[^Lele^]

Thanks for the input. How do I set the number of IPR rendering threads? Or is this feature only available in Corona? I'm really stunned that such a terrible UI experience can exist in 2021. 3ds Max probably has one of the worst UI of any software I've used in terms of interactivity.

It is indeed unfortunate: it hasn't aged well, and less so as they started the transition to Qt.
It'll all be better once we're over the bridge.

As for setting cores, did you try the test i outlined above?
If that works out fine for you, with the standard UI components, then perhaps it's a case of threading, but otherwise it's just comms making the UI slow even further, and reducing threads won't change much at all (as core0 is waiting, not processing.).

[Muhammed_Hamed]

How do I set the number of IPR rendering threads? Or is this feature only available in Corona?

Setting this to -4 or -8, still lags the UI in Corona's case. You need to exclude 12 or 16 Threads to see a difference(which is a big trade-off, not a real solution), it is very odd
I'm not sure if this parameter works correctly in Corona or if it is related to 3Ds Max itself. This option doesn't exist in Vray for 3Ds Max plugin, it exists in Vray Modo/Houdini/Maya(I barely ever use it there)

I'm really stunned that such a terrible UI experience can exist in 2021. 3ds Max probably has one of the worst UI of any software I've used in terms of interactivity

This is exactly what I thought, coming from Houdini/Maya/Modo/C4D .. Only 3Ds max's UI lags horribly like the video I posted above
It took me a lot of time to get used to it, and I'm glad the issue is minimal on my current machine (I sold my 2990wx last year)

Try Lele's suggestion, it will help narrow down the issue
I honestly don't think using an all-core OC for these CPUs is a good solution, you lose on single-threaded performance and it takes very long time to find stable voltages, and you need very good cooling

Best,
Muhammed

[algato]

Hello,
may I ask,
are the current Intel processors free from such a problem ?
Are the lags only AMD specific ?

Best regards
algato

[Dman3d]

This may explain a few things I noticed when we switched to 5900x processors. Lele, any notes from the dev team or when the Qt work will be done and ready in an update?
And just checked, yea slate is super laggy.

[AbeTJH]

So I did a similar video and test with my machine using Vray 5 Update 1.3.

https://vimeo.com/631075891

I have the notorious 2990wx although we have also observed this on Threadripper 1950x as well. In my video I changed the environment VRAY_NUM_THREADS to 54 but it does not seem to help.

Do we know when the Vray Material Dialog will be written in QT? As you can imagine this behavior is frustrating.