What I want to do is create a dorm full of sims to my own specifications, but I only want to actually play one of them. I want the others to function the same as the ones that the game generates to fill vacant dorm rooms. So, I created a couple of students, moved them into a dorm, chose rooms for them, invoked the testingcheatsenabled code, and changed one of them to non-selectable. This sort of did what I wanted, i.e. I now only had one sim to control, and I could interact with the other one the same as any other game-generated sim. But he didn't seem to behave quite right. He mostly just stood frozen in one place, unless another sim was interacting with him. He seemed to be waiting until hitting desperation need levels before tending to them. So maybe this isn't exactly the way to do what I want to do.
Is there a way to do what I want to do? Any tips would be appreciated.

You'll need the following hacks: nodormieregen (from Pescado's director's cut at MATY) and the Simblender from Simbology (assuming you have Pets or higher installed).

Since you've already opened your Uni neighborhood, it may be too late for nodormieregen to do its magic, since the game auto-assigns dormies and there will already be some in your neighborhood. However, in a CLEAN Uni hood generated from an empty template (also available at MATY), with that hack installed, any dormies you create will be the only dormies in the pool.

Create a YA in Uni CAS, move them into a dorm, and use the Family > Make me a Townie option on the Simblender. Voila! Instant dormie. Again, since you undoubtedly have game-generated dormies in the background now, this method most likely will NOT keep the new dormie on as a resident in your already-played dorm. To ensure that happens, you would need to muck about with SimPE in ways I am not familiar with.

Creating a new uni hood for this project won't be a problem, so this should work for me. And I've bookmarked that "director's cut" link; what a great collection of hacks. Thanks so much for your help.

Not just a new uni hood, a new uni hood in a neighborhood that hasn't had a uni previously. Unis will share dormies if you have two unis in one hood. You can also use Inge's teleporter (from simlogical) to make dormies, that's how I make mine. If you don't care what you get, as long as they are not the template dormies, you can use the townie generator to make the dormies (turn testing cheats on, shiftclick on your playable, spawn, NPC and Townie maker). But you might get some interesting dormies--especially if you have towniefied untuckables and other interesting outfits. (I once had two dormies with the police uniform in the same dorm when I had a hack to unlock the career uniforms.)

When you add a university to your neighbourhood, the game will generate 50 dormies. The only way to prevent this is to use clean templates and no dormie regen BEFORE you create the university. Nodormieregen should not be removed or the game will start generating new dormies as it needs them.

If you delete the university, the game does not delete the dormies - they stay in your characters folder and are now permanently a part of your neighbourhood. If you add a second university, the game will create another 50 students - all to the same template as the first which is why you will get two students who look identical. Again this is only preventable by using the empty templates BEFORE you create the second university.

The way the game uses the dormies is similarly retarded. It selects a set of students for your dorm when your student sim moves in. I *think* (though I am not quite sure) that it takes the dormies with the lowest character file numbers first. Anyway, you then move someone new into the dorm and one of the dormie sims moves out. OK, fine. Then you move another sim into a different dorm and the game selects another set of dormies for that lot - again using the lowest number (I think anyway). The point is, it will use the sim that moved out if the first dorm before it starts using new ones because that sim will have the lowest character file number available. This is why, over time, you see the same dormies over and over again. I created about 28 dormies when I made my 'templated' neighbourhood, all of different types (to give variety I thought). I have never seen the higher numbered ones in game.

One thing I've also recently discovered is that once the game has assigned the dormie to a dorm they will not go back in the dormie pool even if the assigned dorm is bulldozed.
I had this happen in my custom hood where I had a DL dorm and one I built myself in play for for the first generation of Sims through Uni.

Well the DL dorm looked fab but didn't really play very well so I bulldozed it and deleted the file from my game. The second dorm I built was simply too big and cumbersome as I suck at building so I bulldozed that one as well and deleted it from the lot bin.

I then decided to use the smaller two of the Maxis dorms as my basic template for the dorms. Made all the changes and plopped down two of each on the campus.

Through the next generation of Sims I only used two of the new dorms and all worked just fine. During the 3rd generation I had a real populace boom so I needed to use all 4 of the dorms when I moved Sims into the remaining two I ended up having no dormies arrive to take the vacant rooms. Went through a process checking that the dorms were fine but still no dormies. Seems those dormies originally assigned to the now deleted dorms were still not available to be reassigned.

Via the help thread here I discovered that the game assigns them a "key" to a dorm room and the only way to delete it is via SimPe. One would almost think it would be a bonus to have no dormies show up but it was sort of boring not having any of them around.

For those that already have a Uni hood with the default dormies, is an alternative way to change the DNA and look of the dormies in SimPE rather than starting over? Its probably more of a hassle but would that still work fine?

As long as you just want to change the dormies' appearance, the Sim Blender is adequate for that, and gives you the option of facelift or change appearance. I usually end up doing this with the townies in my 'hood anyway, and so far have had no problems. Christianlove (sp?) created a downright godlike device that allows you to change skintones and body meshes as well; it's available here, but I'll be darned if I can remember what it's called.

Thanks for all the input. I hadn't seen the reply about needing not just a new uni hood but a new hood entirely, so I'll be trying that next. But I did install both nodormieregen and Simblender. I created a new uni hood, using a SC4 terrain (for future reference, does that count as an empty template?). I placed a dorm, created two sims, and moved them to the lot. Once there, I used Simblender to make one of them a townie. Then, I had the same problem I had when using testingcheatsenabled -- the new townie sim seemed to have no autonomy at all, unless a need became critical. I'm wondering if the problem is due to a conflict with another hack, of which I have a good number installed.
Here's another thought -- can Simblender or another utility allow me to re-wardrobe game-generated dormies? Not just select which outfit they wear, but replace their wardrobe with new choices? So, for instance, I could create a 1950s campus and have all dormies wearing period clothing. I'd still be left with drop-ins dressed inappropriately, though. Luckily, the mascot uniforms are timeless.

No that's just a terrain - the term 'empty templates' refers to a process of emptying some of the EAxis game folders and deleting files and replacing them with empty folders. To do the university templates, you need to visit the University game folders on your C* drive (not the folders and files in My Documents). You also need a replacement neighbourhood file I think - I can't remember, it's been a while since I did it but you need to read the MATY thread for the full instructions. It's not hard to do but you need to make sure you delete the right files (keep a backup just in case). Basically, you are making a permanent (though reversible) change to game files so you need to be sure you know what you are doing.

* assuming you installed on the C drive

Edit:
The other thing that has just struck me Bill is that it sounds as if when your new townie sim is created that they stay on lot. When I've done that, they leave immediately. Maybe that's your problem. I'd try deleting them. I'm trying to remember now how you are doing it - if you're using a hack, it might be different. Anyway, if you are doing it with the townie gun they should be leaving.

Edit Edit - oh wait, you are making them unselectable. That doesn't make them a townie, it just makes them lost. No wonder they aren't leaving the lot and are standing there doing nothing.

The Simblender will not allow your Sims to change into outfits that are not in their inventory-they need to purchase them as usual, or acquire them through one of the many hacked objects that will give them new clothes for free (you still need to choose the clothing, however).

Actually I remember from when I created my custom Uni that you cannot use a dorm lot to make them dormies. I plopped down a small empty lot and put all the needed hacked items, SimBlender, hacked clothing rack and so forth on it.

I created my Sims in CAS and from the Sim Bin moved them into the empty lot (it's pretty cheap since there's nothing on it). From there I used the blender to randomize their personality's, skills and so forth and then turned them into a townie.

Once you make them a townie they will turn and walk off the lot so make sure you make any changes you want to them first.

You can also use the SimBlender to teleport existing Sims onto the lot, make them selectable and if you have a hacked clothing rack change their outfits. Simply make them unselectable and then clear them off the lot.

I can't remember the reason but I know you can't use a dorm for this purpose, so that's probably why you are having so much trouble with it.

You can make townies that are dressed appropriately for a themed hood--people do it all the time. But you need to have the custom clothing first. Then you can just temporarily move the townies into your active "family", change their whole wardrobe, and set them as townies again. (On that note, it is a LOT easier to just make/download default replacements of the Maxis clothes when you run a themed game. Then you don't have to worry about manually replacing everyone's outfits, or having twenty million extra clothing items in your catalogue.)

Lazzybum--Yes, you can do that. Go over to MATY in Pesantry and get the tool by Theo called alt sim surgery (you don't strictly need this, but it means you can use any saved sim instead of one existing in game which is what you have to have with regular sim surgery) and follow the directions. It's pretty easy--at least I was able to do it with no trouble.

Do you mean Christianlov_SimBoutique_ClothingRack? (That's the filename in my dl folder). It looks like the expensive rack of clothes and you can use it to buy clothes for free, change townie/downtownie clothes (as long as they're in your wardrobe), and makeover any sim in the game. With the Change Appearance option, you get the CAS face modifer screen, so you can plastic surgery the sim in question, then the hair/makeup options you get with a mirror. The plastic surgery is only skin deep though, it won't change the genetics of the sim, so you can get some kids that look nothing like their parents whatsoever, as they will inherit the original face template/s.

I adore this mod. It has beautified more townies in my games than I can count. I also use it whenever I start a new hood to change all the premades into decent clothes.

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I always have to create my own dormies and generally start with the premades I'm not interested in playing. I move all the binned ones in with the housed ones and change them into townies on the lots (like Clashfan I've never done this in a dorm, but have never had any problems doing it on a lot). The first sim created will be the first one to claim a room in your dorm, second created next and so on.

If you don't want a particular dormie living with you anymore, you can also replace it quite easily. Using boolprop dormspecifictoolsdisabled false, move the Myne Door of the dormie you want to leave to be inaccessible (don't delete it yet) and put a new door in it's place. Within a few minutes a new dormie should turn up and claim the door. If you're happy with the new one, delete the original door and ask the rejected dormie to leave/say goodbye. If you want someone else, just rinse & repeat! This also works for the whole dorm - just do all the doors at once.

Taking this this even further - I have made dormies selectable and had them drop out. They end up in the bin of the main hood and then I move them in to an empty lot and townify them again.

That's a brilliant idea! I've got some that have just been around forever that I'm sick to death of. Maybe as a townie they will win the lottery and get picked as a mate by one of the playables.

I do this for that exact reason. It gets really boring having the same load of them every time I send a sim to college. I rarely send more than one at a time, so only ever have one active dorm. Which equals always the same dormies for me. I don't seem to have the same problem as Clashfan -

Currently I have 14 students at Uni but only 2 of them are still in a dorm. I'm getting ready to send another 10 or so which is the reason I have 4 dorms. They only get to stay in the dorms for Freshman year and then have to move out.

I rotate them through to keep siblings in sync in terms of age difference, plus I really like playing Uni.

I hardly ever play anywhere except in dorms. Maybe the odd Greek house now & then, but I like the randomness of dorms. I tend to build them quite big, with lots of space for fun objects. I always have a pool table & a card table. The dormies only ever get 2 squares & a Myne Door - their rooms are empty, I discovered a while back that they don't actually need furniture. Handy for large dorms - I can get up to 16 or so dormies before my game slows too much to play smoothly.