ZBrushCentral

RAM upgrade

ZBrush Usage Questions
#1

Dear all. I am starting to think that maybe I need some more RAM for my machine. I have been working on a model, with four subtools, the main tool itself, at level 5 is about 2.5 million polys. When I go to subdivide again I get told that there is insufficient RAM to perform the operation. I have had this message other times aswell. Would it help to unclog my computer of files I dont really need/use, or should I just buy some more ram? I see on this forum of models stretching up to 40 million polys or more. I think the most Ive seen on my computer when using zbrush is about 6 million.

I wouldnt know where to start looking for extra ram or how to install it. Would some extra ram really make a noticeable difference? Or is it fundamentally the speed of my processor? I’d appreciate any advice…

#2

How much RAM do you currently have? You can find the system properties in My Computer > View System Information (side menu). What is your operating system? I went from 2 gigs to 3 gigs on XP and it made a little bit of a difference. I was able to get one more level of subdivision, but performance sucked. XP has a limit of 3.5 gigs of RAM, but windows 7 is virtually unlimited. I recently priced a new computer with a quad core processor, windows 7, and 8 gigs of ram at around $700.

If you have half a gig of ram or something, it probably worth upgrading with more ram. I am able to have as many subtools as I want with up to 2 or 3 million polys each with 3 gigs. I don’t feel limited, but high quality renders take a while. I’ll probably upgrade as soon as possible.

The way you get more ram is go to best buy, tell them what kind of computer you have, and they’ll sell you the ram. It should cost about $50/gig. You may want to bring your computer with you if you don’t know how to install it. It’s pretty easy, but if you’ve never done it, you might want to see it done first.

On a side note, you might also get more breathing room by removing unnecessary edge loops from your low poly model. You can also chop it up into smaller subtools.

EDIT: The guys with the crazy models are using windows 7, and don’t worry themselves about huge poly counts. Also, unless your hard drive is almost full, cleaning up old files won’t make much difference.

Good luck!

#3

Thanks for the reply ioster… hmm, I wonder, does zbrush perform better, like, economize more, when you have the total number of polys shared between many subtools rather than all in one object? Like say I have a model thats 8 million polys, and Zbrush wont allow me to subdivide further, would it be better to have four subtools with 2 million polys each? If you get what I mean.

I have 32 bit vista OS, 4 gig of RAM. My computer cost me about £730 when I bought it last year, so it shouldnt be a slouch exactly. Ive been told that 32 bit OS’s put a cap on how much RAM can be used, so it would be worth my while converting to a 64 bit. Maybe with Windows 7. Then i might be able to go up to 8 gig of RAM? Im worried that if I convert my OS then i’ll lose some of the programs and installs on my computer as it is. But I’d definitely like to find a solution. I dont want to be capped at 5 subdivision levels for ever.

#4

As I understand it, zbrush is not a 64bit application so even if you add more than 4GB of ram it won’t be able to access it (sure someone will correct me on this if I’m mistaken). You will benefit in that the ram that you do have can be shared between zbrush, other programs that are running and the operating system, so overall you should see benefits.

Going from a 32bit vista to 64bit win 7, you cannot do an upgrade option. You will have to do a custom install. Your documents and settings can be moved across later using the Easy Trasnfer wizard but you will have to reinstall any programs.

Richard

#5

@Richard - I have only anecdotal evidence, but the few people I’ve talked to (at work and on the forum) have described huge increases in performance.
I’m not sure about zbrush being limited to 32 bit either. It sounds like El Dorado, to be honest. I can’t even imagine what it would be like to have a 25 million poly sub tool. I bet it’s pretty cool.

I do know that I was able to get a whole lot more polys by dividing up my last model. I also removed a bunch of redundant edge loops from the low poly version. It seems a little counter intuitive, but zbrush seems to perform much better with ten 1 million poly subtools than one 10 million poly tool. One problem I haven’t solved with dividing up a model is getting a smooth transition from one tool to another in a contiguous form, like a shoulder meeting a torso. I’m sure it’s possible, so if anyone knows, lets hear it!

If you already have 4 gigs of ram then you may be out of luck short of installing 7. However, I am surprised that you are having the kind of performance issues that you describe. Can you post a screen grab of the low res model?

#6

You will have better performance with multiple subtools as the polycount limit from your ram is per subtool not the total number of polys across all tools.
If you get a message saying you can’t get another subdivision you can also change the max poly number in the Mem settings.

The point about it not being 64bit is that you will hit a ceiling in number of polys when you max out the available ram that zbrush can use. If its 32bit, give it 16GB of free ram and it’ll be the same as giving it 4GB of free ram. Having more ram will benefit your whole system as it allows all your programs to have as much ram available that they need.

Richard