Instancing slow down

[amitc]

I am trying to instance few primitive geometries (sphere and cylinder) by reading their coordinate info from a txt file also doing some vector computation for finding orientation (rotation, scale and move).

1000 objects take about 20 seconds.
3000 objects take about 190 seconds.

When I try to instance all 25,000 objects I need
the script could not produce result in more than an hours time.

I have turned off undo. (also tired turning off construction history)

I am using getAttr could this be the trouble maker

When I create all objects as geometries no instancing entire thing is created in < 2mins, Yeah instancing takes three more steps than creating the geometry (rotate,move and scale)

Is there any limit or optimal number of instances that can be created?

Any clues why this slow down is happening ???

Thanks!

[chadrik]

have you checked your computer's memory usage while running the script? you may just be running low on real memory - that is a lot of geometry to hold in memory at once. perhaps try running the script from the command line without the gui?
-chad

[amitc]

Memory is not a problem. Ran the script over for weekend it could do only 90% of the job in 42 hours and I aborted it.
I have actaully created copies(not instances) of the 25000 primitives which takes about 25 mins on (p4, 2ghz, 1gb)

Seems like moral of the story is if you have more than 1500 instances move to particles.

[tbriggs]

Maya is woefully inept in its memory usage, particularly its so called instancing, which provides no improvement that I could find in memory use versus just duplicating. The numbers you need are far beyond what maya can do. You need an ept software like Renderman to handle this problem. It does this easily with archived ribs, and that is how you get the armies of tens of thousands in LOTR, swarms of creatures, etc. Maya has to load all the models in before it starts to render, which sets an upper limit on what it can hold. Other renderers don't need to do this.

[joojaa]

I belive veta had problems in getting the armies to work in rendeman as they wanted so they had a special renderer makde for this purpose! (it sint as good as renderman but it does the job!).

Also i dont think his talking about rendering the stuff he has problems in making the stuff. But yeah if used in render they would be exactly like copies (actualy this would partialy be true to renderman too but renderman is much more agressive at loading away gea trhan most renderers, wich kindoff makes me wonder how how can make it raytrace at all eficcently but it does this too... quite well)

[amitc]

thanks for your thoughts!
As Jooja pointed I am still struggling at object creation,

after that rendering would be pain in neck perhaps I'll be setting up a render farm

this is far fetched idea but can maya be parralleized to some extent ???

[tbriggs]

I'd be willing to bet that what they did was instead of calling a rib sequence the call would be to an external application that assembled the rib from bits and pieces of models and action so that there would be a great deal more variety of action. It's cool but that one is beyond me.

As to working with large numbers of things what makes Renderman so great is that it only loads what geometry is needed for the particular bucket it is rendering, and the delayed read archive methodology allows for levels of detail.

[joojaa]

Yes offcourse but I heard that atleast the first movie used a properitary renderer. For the mass scenes (the source was a bit vague on this so maybe they only used it for the distant characters dunno), now if id only remeber what the name of it was... But yeah they would use a ribgen offcourse.

[campbell]

GRUNT, acronymy of something along the lines of General Renderer of Unlimited Number of Things, w Massive as the generator of Things.

[joojaa]

Yeah that was it...