Since the installation of Corona 12 update 1 i have very slow (unworkable) viewport performance when Cosmos is open. As soon as i close Cosmos the viewport acts normal again. I noticed Cosmos no longer opens in a seperate browser window too. It looks like it is related to this maybe?
Anyone else noticed this?
edit: i would like to add that it doesn’t happen if the viewport is light (not many polygons).
If possible, please check if it’s better for you in the latest daily build:
https://forum.corona-renderer.com/ Chaos Corona 13 for 3ds Max - Daily Builds Changelog #msg230430
Yes, the update fixed the problem. I do notice something else now though. I always open Cosmos on my second screen, but now Cosmos is on top as soon as i start working in 3dsmax. I often have a pdf or email open on my second screen but now i can’t see it when Cosmos is open. I liked it better the way it was. A seperate window could be active whenever i needed it, now it is always active as soon as i start working in 3dsmax and i have to close or miminize the window.
I also just noticed that opening Cosmos messes with the pulldown menu when Cosmos is open on my secondary monitor. I use a small 10 inch screen for this and sometimes the pulldopwn menus seem to take on a different resolution or the flyouts in the pulldown menu don’t work 
Hi, what exactly do you mean by the “pulldown menu” and “flyouts in the pulldown menu”? Could you share a screenshot of what is wrong?
See the first screenshot. The menu looks normal (Cosmos has not opened yet)
The other screenshots are with Cosmos opened. Closing Cosmos does not resolve the issue, i have to restart 3dsmax to get the menus back. The 3rd screenshot isn’t showing anything when clicked on.
Strangely the tools menu acts normal.
Thanks for the details. This is odd. Which version of Corona and Cosmos are you using?
I am using the version you linked me to in the previous post. This behavior started with the update which gave Cosmos it’s own window instead of a separate browser window, also notice my reply on the 24th about this.
I also have my text set to a 150% scale on the secondary screen. The resolutions of my screens are 2560x1440@170hz for the primary screen and 1920x1080@60hz for the secondary screen, the secondary screen is below the primary.
This is now reproduced and logged for our devs.
(Report ID=CMAX-1462)
It happens when using two monitors with different DPI scaling settings. The workaround would be to use the same scaling on both monitors.
Yeah, i figured the scaling was the culprit since the letter got so big. Are you also looking into Cosmos always being in the foreground when using max. It was better in a separate window.
The issue still remains to some degree. I have a scene with a large multiscattered grass plane. When i start render the mousepointer gets very laggy, this is both with IR and production render. As soon as i close Cosmos the issue is gone.
(Un)fortunately, this is a 3ds Max issue unrelated to Corona. It happens even if you uninstall all Chaos products.
Than why doesn’t it happen when i close Cosmos? Can you explain this?
Same Problem here, Viewport super laggy when Cosmos Browser is open.
Corona_Render_12_Hotfix_01 was fine. Now Corona_Render_12_Update_01 is having problems. How can this be a 3ds Max issue?
Do you have Cosmos open on different monitor than 3ds Max? Do you have different scaling on both monitors?
If you take any 3ds Max dialog (for example “Render Setup”) and move it to another monitor with different scaling, you will get the same issue.
I am guessing both 3ds Max and Cosmos use the same UI framework and it glitches in the same way.
3ds Max issue is “UI items appear in wrong places/wrong scale”, not “viewport laggy when using Cosmos”.
Regarding the laggy viewport - what is your CPU model? Is this happening in any scene? (even empty?)
I just tried it with the render setup on the second monitor and no lagging occurs. I do have different scaling (that is the issue we found before). I am talking about the lagging here, not the pulldown menu’s having different scaling.
3ds Max issue is “UI items appear in wrong places/wrong scale”, not “viewport laggy when using Cosmos”.
Regarding the laggy viewport - what is your CPU model? Is this happening in any scene? (even empty?)
It only appears in more heavier scenes with lots of polys.
CPU: AMD Ryzen 5950X 16 Core
GPU: RTX 4060
For Erik1974 the issue of lagging when the Cosmos window is open was fixed by installing the newest version of Corona (Corona 12 Update 1 Hotfix 1) - Download | My Chaos
