I'm new to attempting Portal speedrunning, and recently installed and set up the speedrun demo recording software. I've tested out some of the available commands, but I'm having difficulty loading challenge maps.

In this specific case, I'm able to load Chamber 17 with

speedrun_map testchmb_a_13

but I'm unable to load challenge map versions of it - in this case, the Least Portals Challenge Map for Chamber 17.

I've attempted

speedrun_map scripts/challenges/testchmb_a_13

but it returns the error:

CModelLoader::Map_IsValid:  No such map 'maps/scripts/challenges/testchmb_a_13.bsp'
map load failed: scripts/challenges/testchmb_a_13 not found or invalid

I'm unfamiliar with the back end of Source, so if anyone knows how to specifically load that script version of the map, it would be greatly appreciated

Thank you!

The challenges aren't their own maps, only the advanced chambers are actually different maps. You can change the value of sv_bonus_challenge to 1, 2 or 3 (for least portals, least steps and least time respectively), and when you then load a map it'll activate the overlay for as long as you have that map loaded (saving/loading saves within the map works fine, but fully restarting the map or loading another map makes it disappear again).

Do keep in mind though that this is not allowed in speedruns (which includes Least Portals) since it changes the way that the level transitions at the end, I've added a bit to the Least Portal IL rules to clarify this. The Least Portals ILs work pretty much the same as base game ILs, a short guide on how to do & record these properly can be found here (only the demotimer mentioned there shouldn't be used anymore I think, use UntitledParser or startdemos+ instead).

Alrighty, I'll have a look at those. Does this mean that I should also set LiveSplit to automatically split at the end of the chamber if the settings support it, to help remove user error in timing? I've been timing by hand while practicing and it's a bit difficult to continue moving correctly while thinking about the timer.

I know that the demo recording displays the correct time, but I don't know how to read the contents of the demo file and don't want to create a time discrepancy.

Since the IL rules require you to start on the previous map and then load into the map you are actually running, it's easiest to time this using two splits. This way you can just manually start the timer whenever you load your IL save, it'll split when it transitions the map, and it'll then stop the time when you finish your run. So your final time is just gonna be the segment time of the second split. In case you don't have your autosplitter and load time removal set up, as long as your game is set to Portal it should show the settings for that in the Edit Splits menu.

Also timing demos is pretty simple, you can get UntitledParser and just drag a demo file onto the exe. It'll open a window with all the general information about the demo, most importantly the total time at the bottom, in seconds aswell as ticks (1 tick = 0.015s). You could also play your demo back ingame with the Shift+F2 demo UI, that'll display the total ticks in the demo (just make sure to add 1 tick to this for the final time, since the ingame UI doesn't account for the 0th tick).