Problem switching back to default RHI after using Vulcan

[PalCorral.jacob]

I switched our project RHI from default to Vulcan about 2 months ago to avoid a recurring crash when exporting timeline animations within unreal editor. Since neither of us has preferred using the built-in animation editor over Blender, I decided this morning to switch back to the Default RHI, which I believe to be DX11.

This seems to have caused numerous problems. In the editor, a mesh that is very far from the camera is flashing with a graphical glitch. This goes away in PIE but everything runs very poorly in editor and PIE.

I’m not really sure what information would be useful to provide, I have zero high level understanding of what is happening. I know that when I switched to Vulcan it took about a half hour to recompile the shaders the first time we ran the editor again, and we ran into some wierd behavior then, too. This time it only took a few minutes. I’ve been playing with the project settings but its all a shot in the dark.

The only other idea I had was maybe to delete my defaultengine.ini and replace it with one from a new project?

EDIT: I made a copy of the project in which I had switched the RHI back to Default. I opened it and switched it again to Vulcan and then restarted. It re-started VERY quickly without having to compile the shaders and is running just as smoothly as before.

This seems to tell me that when I switch it to Default and accept “Restart editor” that it isn’t really doing whatever it needs to do?

…We are running 5.2.1 by the way.

[PalCorral.jacob]

Bump

[PalCorral.jacob]

Finally came back to the issue and got it worked out.

Firstly, in the project settings, when I switched the windows RHI from Vulcan to DX11, I am prompted to restart the editor but when I confirm the editor restarts without recompiling the shaders. I was able able to get the recompile to trigger by toggling some other check boxes in the render settings.

Secondly, I had another issue I was unaware of (didn’t seem to bother vulcan) where the secondary monitor I was using with my laptop was set to a refresh rate that was not a multiple of the refresh rate used by my laptop.

These two issues where combining to create a confusing result but I’m now up and running with DX11 again.