An easy fix from Valve's side would be adding depot 622 (portal 2 win content) as a dependency of appid 629 (Portal 2 Authoring Tools - Beta).
A user fix is to download depot 622 using the Steam console command download_depot 620 622 and copy/symlink downloaded files to the game's bin directory.
In addition, Proton 5.0's DXVK fails to render Hammer world views properly; set PROTON_USE_WINED3D=1 %command% as launch option for the SDK to work around this.
The above comment indeed works, but there's heavy flashing in all viewports when using hammer (also happens in base WINE)
The flashing is bad enough that it's pretty much unusable, at least for me.
However, outside of that, whenever a wireframe is attempting to rendering in the 3d viewport, the whole viewport goes black outside of a single diagonal stripe.
Portal 2 Authoring Tools (629)
Issue transferred from https://github.com/ValveSoftware/Proton/issues/8279.
@Hex4dec posted on 2024-12-01T16:30:53:
From Proton version 5.13:
steam-629.log
Does not launch at all. Some 4.x and 5.x Proton versions take slightly longer to crash, but no window appears.
Launch the game.
@Hex4dec commented on 2024-12-01T16:46:30:
I could've sworn there wasn't an issue for this, but apparently there is: #1278. I have reproduced the fix for this (downloading the depot) and it works. However, this hasn't received an official Valve statement and the issue doesn't look correctly formatted so I'm letting other people close this if needed.
proton 5.0x1 2020-07PROTON_USE_WINED3D=1x1 2020-07PROTON_USE_WINED3D=1 %command%x1 2020-07tier0.dllx1 2018-09vstdlib.dllx1 2018-09
Portal 2 - Authoring Tools (629) SDK Launcher and tools don't work in Steam Play because of missing dlls that contained in Windows version of Portal 2 like tier0.dll, vstdlib.dll...