Rocket sentries and energy balls in P2
Hi, I'm Otto and I'm new here.
I have yet to start mapping in Portal 2 as I am having some sort of issue with Steam that's disallowing to download anything at all (if anyone can get me like a download mirror that would be awesome as Steam has yet to get back to me on this problem). However, once that's resolved I'll definitely join in the mapping fun.
Anyways, what I wanted to ask about: Remember the rocket sentries and energy balls (High Energy Pellets) from P1 that were absent in P2? I read somewhere that they, while not in the in-game puzzles, are still hanging out somewhere in the game codes. The only other information I know is that the energy ball has no texture. Would it be possible by some means to add these to a Portal 2 map? I have some nifty ideas, like using Conversion Gel with the Energy Ball or using Repulsion Gel with rocket sentries?
Anybody have any ideas about this?
To my (granted, very limited knowledge) the models and code is still there, but they are missing materials and animations.
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I have contacted them, they have yet to get back to me for some reason. No, my version's legal but I got a hardcopy as opposed to downloading it through Steam. The issue may be related to that. I've heard lots of people have issues with Steam and frankly I'm not that fond of it either.
So anyway, do you think it would be possible with a bit of elbow grease to put them into a custom map? Also, would it be possible to have it so that it can be used just using the map without having to install any other mods or whatever?
I am pretty sure that the Combine energy ball is a base Source entity, and it looks like the most fundamental elements of the energy ball puzzle are here - the ball launcher and ball catcher. I have no idea if they work though. Assuming all of the code for these entities is here, you would just need to create a new model for the ball launcher and catcher. Probably sounds and materials for the energy ball as well.
EDIT
I take it back. There are both types of Launchers there - point_energy_ball_launcher and point_combine_ball_launcher. But there isn't a Catcher entity. So you would need to manually build one using triggers. Not sure if that is possible, I've never tried personally.
But, yeah there are no materials for the energy balls so you would need to make new ones. As well as new models, textures and animations for the launcher and the catcher.
Good luck.
EDIT 2
Okay so there was never a specific Catcher entity. Why don't you try following this Portal 1 ball launcher and catcher tutorial and ignore the missing models/materials and see if it still works?
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I'll try that once I get this Steam problem fixed and can download my tools! 
And it wouldn't be too difficult at all to throw the textures in there, would it?
What about Rocket Sentries? I know code still exists in game for a rocket projectile, not sure if it's the same one the sentries used though. I think I'm going to mess around in a playground for a bit and shoot rockets at Repulsion Gel to see what they do and what effect it could have on tests. Even if the sentry is permanently gone, do you think it would be a stretch to make something else that shoots those (maybe like button activated)?
EDIT: Unfortunately the gels have no effect on rockets... Ah well. Still want to see what else can be done.