Hello...I'm new here, and...I was wondering...can I convert .sim file to 3DS Max? I still can't figure it out... help...?

No. This has a reason. Everything the game saves, are data. Sliders are data (Which means you'll get a default head mesh if you would succeed to rip it with programs like ninja ripper). The clothing and it's colours, are data. The sims 2 however, it works differently and you would succeed to have your sim with the shaped head.
The reason why EA did this is probably, because else your sim files would be giant, because it needs to save whol meshes and textures and it would be probably 400 mb to maybe even a GB if it would have been this way.

So, the only thing you could do, and i've done myself, is shaping the head default sims head in 3DS Max into what looks like your sim.

oh...I see...Thanks....

I wonder if the statues you can sculpt of your sims can be exported.

Oh wait I remember- you can use a program to rip models directly off your screen.
https://facepunch.com/showthread.php?t=1178695

Pretty old info, dunno if it still works. Apparently the UV mapping is all messed up upon export, but that's relatively easy work to fix.

@Greenplumbbob - you mentioned something about the sim textures being compressed onto one image- maybe that's the key here?

Well Sliders don't affect the uv map and texture IF EA made it possible to export the sims with everything in one, instead of just data.

I tried ripping sims a few months ago, but whatever ripper I used, I kept having a default version of ts3 bodies and faces. So even if I ripped a fat sim, it still would appear as the normal sims body. I actually made a post back here how accessories works but it does show you how body textures works: http://greenplumbboblover.tumblr.co...ory-gets-blurry
It was in one of these packages but i'm not sure: CASPartCache.package or simCompositorCache.package It's one of the caches files you usually would delete.