Get a pc.

Parallel is terrible. Problem fixed.

I'm not going to get a PC and am going to give Parallels a try for now over Bootcamp, so if that's your advice, don't bother.  

Again, I have near infinite space internally on my laptop, I'm just wondering how much I should devote to parallels.  As of now I have it at 100 gigabytes devoted to Windows 10 on Parallels 10.

Bootcamp > Parallels by a cubic light-year, if you want my advice, from experience.

Thanks.  I've run all the mcneel and autodesk programs, add-on's (vray, grasshopper, tsplines, climate___), and various games on parallels before w/ fine results, so I'll be sticking with parallels for now.  

I was going to devote 500gb of my internal hard drive towards my windows 10 virtual hard drive for no other reason than I had it to spare, but thought better of it and set it to 100 gb.  

Now that I've explained why I'm sticking with what I know for now, if you don't have an actual answer to my question, I'd appreciate it if you refrained from commenting.  

Thanks for trying to be helpful, though!

If all you need is space for the software, half your drive seems excessive. Can the windows drive write to the mac partition? See those files? Do all of your files on the PC side need to remain on the PC partition? Revit files can get large, and I have seen folks who are working with workshared files append timestamp to the point where they ran out of space. Also consider that Photoshop loves to write large swap files, so you don't want to throttle that...

is 100GB a good number, then?

I'm looking for a nice safe number that can stand up to heavy use (particularly Rhino, Revit, and Autocad).  I also currently have Mass Effect 3, GTA 5, and Batman Arkham Knight on virtual disk as well.

ME3, GTA, and Arkham shouldn't bloat too much after install, but like I said, it all depends on where your working files will be located as well as your swap files for the other installs.

For reference: I have about 200 GB on my boot drive and a secondary 1TB storage drive. I work just fine, have yet to need more space, and I am currently using about 140/200 GB on my boot drive and 100/1000 GB on my storage drive.

Partition more space than you think you need. My employee has an MBP that we partitioned to run ArcGIS. We first partitioned it with 50GB. We found to run Windows 8 alone uses 30GB. Then to install our dropbox, we were already over 80GB. We ended up repartitioning the HD with 150GB. That's fine for just ArcGIS, but you sound like you are using more intensive modeling and rendering programs. I would recommend at minimum 200GB for what you want to do, but would seriously consider devoting more space. If you have to repartition the drive, you will have to reinstall all your software and resave all your files, i.e. it's a big pain in the arse.

(BTW parallels has been totally solid with everything we've tried to do on the PC side of the machine.)

I used to have a strong dislike for virtualization, but that was back when it was built on virtual architecture that was unable to see multiple core machines at their full potential. If your hardware can handle it, it's a great concept that removes a lot of the unnecessary rancor from the PC vs Mac bicker battles.

Alright, I'm going to go with 250GB, thanks!

I have 42 and 48 inch Maylines, allow another 12" for board width.

I miss my Mayline. One day I'll set it back up on a fresh board. Until then, my always reliable 45-degree square will do.

McNeel advises against running Parallels.

My MBP died young, 3 years old. I think the problem was overheating from running Bootcamp, and apparently Parallels is just as bad.  I'd look into heat management workarounds if I were you.

Honestly run pure Bootcamp. Parallels is not for architects IMO. You want all your hardware dedicated to one OS. When the Apple OS changed to Yosemite, Parallels wanted money for a upgrade so that their software will work with the new OS. Sorry but you aren't going to hold me hostage. Deleted Parallels, installed Yosemetie and will never use them again. Also good luck trying to run Parallels and Bootcamp under one activation key. What a nightmare. never again!

parallels makes no sense. bootcamp is better, although I just unpartitioned my hardrive, and my quality of life is significantly better. windows is useless on a mac, just buy a cheap desktop machine for your gaming and whatnot. rhino, cad, adobe etc is all on mac and working fine now.

instead of buying two computers, why not just get a pc?

^ you don't get to claim you're better than everyone if you buy a pc.