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CPU / Memory Usage. Max inefficient? Or my bad?
show user profile  LionDebt
So, yeah, I've been playing around with the Cloth modifier and it's taking an average of 7 seconds per frame, apparently. But most frames last between 4s and 20s. Furthermore, the cloth simulation doesn't appear 'that' realistic.

I've got a plane with 120 height segs, 90 width segs at 45cm x 60cm.

My CPU usage never gets over 50%. Memory is also a constant 2.25GB (50% of total).

Is this natural?

Does the cloth modifier work better when the objects being modified are kept on a realistic scale? (My first attempt was at 450cm x 600cm). I used the Cashmere preset, and it seems to bounce around wildly - as though it was made from elastic and thrown at my collision object (sphere) at 100 miles per hour.

Edit: Also - is there some way to use the cloth object as a collision also? Since, the cloth will clip through itself by the end of the simulation - which isn't very realistic :/
read 1777 times
6/18/2011 1:27:46 AM (last edit: 6/18/2011 1:31:08 AM)
show user profile  killerbee2
welcome to the club ! Yup max is quite inefficient when it comes to using resources.

For realistic cloth simulations there's a couple of things that might help.
I'm gonna add something about it on visualart soon but here are some tips :

Try setting your global scale to 10, I'm trying to find the logics behind it (very badly featured info in the help files of max) but I noticed no difference when setting the max unit scale from cm to meters or vice versa. So my guess is clothfx uses its own metric system.

Unless they're gonna implement the GPU physics into the clothsystem it's rather slow, especially with the amount of segments you got now. Eventually for realistic you can double it despite the extra calculationtimes. But as for now I'd say add a HSDS subdivision modifier on top of your clothsimulation, it will allready create better results. Next to that cloth needs thickness so add a shellmodifier on top of that too.

Depending on what your setup is, start from the default cloth setting before going into the preset types of cloth. Usually it only takes a few parameters to alter to get to a desired result. Reason for this is that the default is the most stable.

To create better creasing and folding, adding some windforces to your simulation helps quite a lot. Set the forces to 0, up the turbulence and lower the scale. If you wanna quickly see the noisepattern it creates, simulate locally without gravity. To get rid of a pattern, use several winds with different turbulence amounts, different frequencies and different scales. Even more advanced is you animate the values over time.




read 1767 times
6/18/2011 1:42:48 AM (last edit: 6/18/2011 1:46:28 AM)
show user profile  LionDebt
Yo KB, great reply :), if MF had a like button, I'd be pressing yours right now. No homo.



Any way to stop the cloth clipping through itself as shown? It looks fine from very far away, and this would be acceptable for say a render of a restaurant - as table cloths etc, or curtains in the distance. But... perfectionist wants rid of them!

I'm definitely upgrading my CPU in the next few months, this is getting ridiculous :)...
read 1753 times
6/18/2011 2:06:04 AM (last edit: 6/18/2011 2:06:04 AM)
show user profile  killerbee2
i assume you got the selfcollision allready on, next to the self collision there's a spinner, increase that untill they dissapear (it can go up to 10) but again despite simulation times.

Also increase the subsamples in simulation parameters rollout. This is the amount of subframes it will use to calculate the cloth (setting it to 5 for example will increase simulation times x5 :)) But normally with slow dropping cloth onto a table the standard 1 would be enough.

If nothing else helps, there's this old version of clothfx somewhere on the net which does more robust calculation of cloth, the difference with the one included in max is that the subsamples are automaticly adjusted when a difficult situation happens. The old one kept adding subsamples untill the cloth was correctly solved. (I once did a simulation of highresolution cloth twisting around each other that went up to about 300 subsamples - the old robust one was the only clothsimulator who could handle the situation, I tested it to Syflex, Ncloth, reactorcloth and max built in) I should have a look if it's still around...


EDIT: found it -> http://www.spot3d.com/simcloth/files/simcloth3.rar




read 1745 times
6/18/2011 2:50:04 AM (last edit: 6/18/2011 2:54:03 AM)
show user profile  ScotlandDave
Nice info Kb.

One hack for CPU usage that may work for cloth is at:

3dworldmag.com/2011/05/27/how-to-get-the-most-out-of-the-cpu-in-3ds-max/

Basically disable multi/hyper-threading in BIOS, should squeeze a little extra juice out of single-threaded processes in max.

Website | Blog | Contact | Vimeo

read 1717 times
6/18/2011 12:28:47 PM (last edit: 6/18/2011 12:28:47 PM)
show user profile  LionDebt
Good to know, Dave. Thx for that.

But I think the main problem is just that my CPU is ancient and in dire need of an upgrade... I'm too embarrassed to post it's specs.

Just out of curiosity, what are all the processes/modifiers/things that are single threaded 'by nature' in max?

Reactor? Particle Systems? Cloth? Any others to note? Is it basically anything that is not rendering?
read 1697 times
6/18/2011 4:53:11 PM (last edit: 6/18/2011 4:53:11 PM)
show user profile  Mr_Stabby
dont go turning off HT lol, at most you'll get 1% more performance in single threaded tasks at the expense of ~10% (for max) in multi threaded.

Scale of the cloth doesn't matter, what does matter is the amount of verts * how resistant to deformation they are. So the stiffer the material the more it takes to calculate a suitable progression for it, ofc self collision if checked also takes its toll (depending on the precision you choose) and subsample count. The latter 2 are the main attributes that yield higher quality simulation so if you get stuff like cloth going through itself or through a collision object or whatever attend to these 2.

and ye, Ive been complaining for years in autodesk forums about the single threadedness of all things viewport, there was some talk of drawing power from physx for cloth before max 2012 release but they never delivered.

read 1651 times
6/19/2011 1:54:16 PM (last edit: 6/19/2011 1:54:16 PM)
show user profile  LionDebt
Here is when I crack open that can of worms:

Do Maya, SoftImage or Blender offer better capabilities with regard to cloth? Or multithreading in general?
read 1640 times
6/19/2011 3:58:09 PM (last edit: 6/19/2011 3:58:09 PM)
show user profile  advance-software
they are all more performant in general as none of them compile with RTTI enabled as max does (which slows it down).

as to performance of specific areas of specific apps - don't know, but you could run some quick tests. they all have eval versions available.

read 1638 times
6/19/2011 4:00:31 PM (last edit: 6/19/2011 4:05:27 PM)
show user profile  LionDebt
Cool, good to know. The reason I'm curious is because my student license / educational / non commercial whatever it's called - is going to run out in <2 years, maybe sooner. And so I'm going to jump ship and try my hand at Blender and Maya and other alternatives just to get a feel for how they operate. I'd be a sucker to just blindly purchase a full max license without testing the waters, as it were. Although, I love Max and it's all I know - so that is tempting me haha.
read 1629 times
6/19/2011 5:12:26 PM (last edit: 6/19/2011 5:12:26 PM)
show user profile  Paunescudanutz
Blender sounds really cool being open source and all but its so confusing, if you want to try it out you might wanna start with some good tutorials.

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<---~( Daniel )~--->


read 1625 times
6/19/2011 5:21:03 PM (last edit: 6/19/2011 5:21:03 PM)
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