This is my first time trying to essentially build a dungeon. The other adventures I've put together for my group have been outdoor, and I'm struggling a bit on how to put together a multi-floor facility.

The backstory on it is they are being sent by Alliance intelligence to investigate the lab of a former Seperatist scientist who was trying all sorts of bizarre experiments in an attempt to create a superior fighting force - he's loosely based on Dr. Mengele. Quite by accident he discovered the known universe is actually a multiverse and he created numerous convergence gateways inside the facility to slip between universes. What he didn't realize is every time he moved around it made him slightly crazier until he totally lost it. He booby trapped his lab complex, but built in solutions just in case he ever got trapped inside one of them. Each universe is basically the same - good people are good, bad people are bad no Spock's beard situations here - but people who have died in some universes may still be alive in others and can be brought across. They are going to face off against different versions of the scientist and his same team of five bodyguards numerous times throughout the facility as he stocked the Alpha lab with various selves he's collected from across the multi-verse.

Anyway, that was just to give you an idea of what's going on there. What I need help with is actually figuring out stuff like how to build the facility. Do I need to make sure there's something behind every door? What's the right size to be reasonably played out in a 4-5 hour session? Does everything need a purpose or should I dump a bunch of red herrings? What about number of floors? I envision it as an underground facility that is entered by a hidden elevator in the middle of a forest, but I don't know how big I should build it, how meticulous I should plan it out, that kind of thing.

I've been careful to make sure anything I know I want inside has a reason for being there and that the solutions to the puzzles have to be fair. Just looking for some additional advice.

How many people occupy it? A place to eat, sleep, wash, work, and storage. A living floor. A lab floor. A mechanicals floor (generator). A warehouse floor. You have an idea of how long a combat encounter takes for your group to judge 4 to 5 hours with searching/investigating on top of that.

As the pirate says: How big do you want it? How long do you want the players to spend there? That will kinda determine scale. Also depending on the situation you can condense a big map into a smaller one through recycling (there may be a dozen 2 person staff dorms, but they are all essentially identical except for personal effects that's 12 rooms for the effort of 1), and if the facility isn't in good condition you can close off areas through sealed hatches, cave ins, ect.

How detailed or not detailed is totally up to you. Personally, I wouldn't go too detailed unless the facility is small. Say 5-10 rooms at most.

Strongholds of Resistance has some information on hidden Rebel Bases, with a little window dressing they could probably be re-purposed pretty easy. There's also Whisper Base from the beginner game of course. If you really want to go nuts, track down Hideouts and Strongholds in the D6 holocron. It's literally just a stack of secret bases, outposts, space stations, and tips on making your own. Finally, if you just want a map of a 7 room hidden underground research base, Look up the Plant Food adventure in the D6 campaign supp Kathol Outback.

2P51:
The facility itself is pretty much deserted at this point. I'm planning on there being 3 or 4 iterations of the scientist and his bodyguards for the group to contend with, but that will be flexible depending on time. The rationale for him and his crew to be there in the first place is a silent alarm the PCs unknowingly trip when they find the entry.

My hope, and we know how players thoroughly thrash GM expectations, is that they will slowly piece together the backstory by accessing various computer terminals on the levels. But I'm sure they'll get two triumphs on the first terminal and learn everything in the first hour. haha

Ghost:

Thanks for the suggestions. I'll check out the old D6 maps.

So if it's abandoned have the computers jacked up and the internal network is down. Information has to be retrieved off of each terminal's cached memory.

Update: Ran it last weekend and it went very well. Stocked it with puzzles and traps rather than enemies. Players loved it. Thanks for your very helpful suggestions 2P51 and Ghost. I really appreciate it.

Update: Ran it last weekend and it went very well. Stocked it with puzzles and traps rather than enemies. Players loved it. Thanks for your very helpful suggestions 2P51 and Ghost. I really appreciate it.

Care to expand on that a little? What kind of puzzles and traps? I just threw together a decryption puzzle for my group last weekend and they loved it, so I am trying to find more cool puzzles that will fit in the Star Wars universe.

I too am curious what you decided on for a floorplan...

You could use the Cybershop Ship from Special Modifications. It's intended as a mobile cybernetics shop/clinic but changing it over to research isn't too much of a stretch.

Whooops, sorry I ignored the questions here. I forgot to check back after thanking everyone.

As for traps and puzzles, I set up through the entire session that everything was completely symmetrical top to bottom. All of the doors were floor to ceiling and all the lights were reminiscent of art deco wall sconces mounted directly in the middle of the wall with equal amounts of light coming from the top and bottom. At one point when the mad scientist was on the run the entire base went black and they got thrown around the room. After a few seconds the lights cam back up and they were free to continue pursuing him. When they got to a door there was a path leading up and one leading down. They assumed he headed down, but they didn't know when they lights went out he reversed the gravity inside. So the ended up going up and out instead of down further.

Another one was just a stupid pop culture puzzle, more for the fun of the players than the characters being able to have any reason to suss it out. When they got into his inner sanctum, they found an image of a compass rose on the floor with pictures of the planets Bothawui and Arkanis to the right of the compass rose. To activate the secret elevator to his final area the characters had to position one PC on the north, south, west and east points, in that order, followed by another PC stepping onto Bothawui and then the final on Arkanis. The bad guy's name was Kelvin Onami. To activate it, they had to enter K.Onami's code. They loved that one. One player even gave me a slow clap and called me a magnificent bastard.

One I didn't get to spring that I wanted to, and still will since they're currently still stuck in his base is your typical big empty Star Wars room with a bottomless pit. But this one only has a ledge on either side and no bridge controls. Onami cloaked the bridge and the bridge controls so they need to do a formidable perception check to find the controls or risk walking out onto the nothingness. They'll need to do a series of coordination checks to safely make it across if they don't find the controls.

For the layout, I decided on a main warehouse level for the top floor, big an open with lots of empty crates. There were battle droids ready to power up and take them on, but we were running out of time, so I skipped that encounter.

The rest of the levels, I actually retrofitted some DnD maps I found online to work for the base. It ended up being four levels with some. Here's links to the additional levels:
2nd Level
3rd and 4th Level

The second level map I numbered and created lab spaces, crew quarters, observation rooms all that kind of thing. Some had secret doors to access other areas, little things that successful perception checks showed them.

Level 3 was the left hand side of the map and the grayed out area is where the Konami Code puzzle was laid out. It then lowered them down to the right hand map and into Onami's final lair.

We ended up having to skip some stuff because they decided they wanted to make a side trip to buy some bacta for the Rebellion on the way to finding Onami's secret base. That's OK though since we left off with Onami escaping and one of their teammates missing. Lots of hooks for next session and more time to explore the base.

there is an excellent clone wars episode with a secret lab, season 3 or 4 if i recall. episode deals with some germ warfare.