After updating Vray to the latest version of Vray (4.20) I started getting occasional problems with IPR and to be more precise, not being able to stop it and close the IPR window. Clicking the red Stop button or the X button on the window doesn’t do anything and I have to kill the Max process in Task Manager. This happens on 2 different PCs here. Unfortunately, I still haven’t figured out the pattern of when it does this. It almost seems that it does this randomly. Anyone else noticed this after updating?
There seems to be some issue with this update that I’m currently investigating that causes seemingly random failures in various places. Looking into it now.
Best regards,
Vlado
Awesome, thanks! 
Forgot to say that, but if you can get me a scene to vlado@chaosgroup.com which reproduces the problem (even if it’s random), it will help a lot!
Best regards,
Vlado
Sorry for the delay. I’ve just sent you a couple of scenes to test. I hope these help! I can send more if it happens again.
Hello!
I tried to reproduce the issue with your scenes (thank you for sending them!) but with no luck so far.
If you could remember the exact actions you did during the IPR session it would help us a lot!
If this happens again, please, describe them as far as you can remember.
Best regards,
Margarita
Hi, Margarita.
Ok, I’ll try to remember the steps next time. Hopefully we can get to the bottom of this.
I’m pretty sure I finally reproduced it; I’m working on a fix and I will send you a build to test.
Best regards,
Vlado
Sounds good! I’m eager to try it out.
IPR has just locked up on me again without being able to stop it. Here’s what I did before it happened:
- I started IPR from the VFB window
- I clicked the Refresh interactive rendering button almost immediately after (by mistake, I wanted to click on the red Stop button instead)
- IPR locked up and I couldn’t stop it or close the VFB anymore.
I’ve just sent these reproduction steps and the scene to Vlado. Let me know if you need more info. I’m ready to test the new fixed build if you have one ready.
I have this from time to time, mostly when I’m too fast for IPR it seems.
I’ll chime in when I can give more info and a scene, but interested in updates!
Indeed, i found the same kind of issues pressing IPR buttons too quickly.
In my case i was entering max into a zombie state, starting IPR, stopping it, and pressing the standard render icon.
Click, click, click to destruction. XD
I think it’s fixed in recent builds though.
That, or i decrepified very rapidly, and am not fast enough anymore. 
Lele, you are just too slow! 
but actually I was talking about scene changes that make IPR hang. Sometimes 3ds max Crashes, Sometimes I just vray errors and have to restart 3ds max, Sometimes IPR hangs and I have forcefully close 3ds max.
it is happening when quickly putting a number of maps in a material for example.
I wanted to bring back this topic. I’m getting this issue as well, using the latest version of Vray Next, update 3.1 (4.30.01 build 00001).
Wasn’t getting this issue with this project until recently, not sure exactly what caused it, I’ve been just adding 3d models that I’ve been purchasing as I go. One way to make it happen for sure (in my project at least) is to scrub in the timeline.
I have something like a lobby scene with random objects. Total polygons 24 million, using an RTX 2080 Ti with latest drivers.
The only way I can access the stop button or the close window X button is waiting until the render is complete done (when it says “done” on the info bellow, otherwise I have to reset Max and reopen my scene.
In my case I don’t think is my computer being slow but something with the UI of the IPR, because my settings are pretty lowres and when it starts rendering it finishes really fast.
I know it is not a solution, but have you tried running this maxscript command :
vrayStopIPR()
It should at least allow you to stop the IPR without having to wait for the render to complete.
@theedge Apologies for the late reply. Will try it next time, thank you!
Hi there. An old thread but I’m having exactly this issue with Vray GPU IPR. I’m using Tyflow in my scene. I have a 4090 GPU. The IPR just sits there after I press stop and will not stop and makes 3dsmax unresponsive.
4090GPU
AMD threadripper CPU
256gb RAM.
VrayGPU6 Update 2
To add…it’s only when I’m using RTX. CUDA does not do this.
I have the latest NVIDIA drivers.
This happens even if you disable the TyFlow? Sometimes it seems to want to calculate after a render, and if you are way down the timeline it could be slow. Sometimes TyFlow doesn’t display its progress indicator in the bottom left.