[Sidefx-houdini-list] DOP's: 20,000+ cube wall

Miles Green Miles.Green at al.com.au
Mon Oct 18 20:01:00 EDT 2010


hehe thanks Rick,
 surprising swapping to houdini 11 has helped get over the 20,000+ mark 
without a crash so far..

we're also using the instance technique and using hbatch to optimize 
memory already..

so far the only bad point of swapping h11 is that we are unable to 
active the individual cubes with a point attribute like we were with h10 
now in h11 this just causes the sim to explode which is a shame as 
activating only we could see was currently moving (via an animated 
bounding box) gave us a 50% speedup ..

p.s. whats the advantage of writting out the SDF? so far we just write 
out the final cubes attrs  as a bgeo point could, its super light at 
around 4mb a frame compared to the 2GB+ of written out by the SDF

M

Rick Fuentealba wrote:
> Ack, good luck with this in DOPs land.
>
> One of the things that can help "optimize" this is using RBD Point Object.
> If the objects are the same size, you can instance the same object over a
> point cloud, and with that you can also use simpler SDF collisions. Also
> writing out your SDF for your RBD objects is essential.
>
> And one way I'd recommend actually running the sim and writing it out, is
> via hbatch or hrender. That way you don't force Houdini to display.
>
> Hope this helps.
>
>
> On Sun, Oct 17, 2010 at 5:05 PM, Miles Green <Miles.Green at al.com.au> wrote:
>
>   
>> Doh as text only version:
>> ------------------------
>>
>>
>> Hi,
>>  we're trying to create huge wall of cubes that collapses after a basic
>> collision with a sphere..
>>
>> The problem is after 20,000 cubes ODE just crashes with a Segfault on
>> our 64bit linux v10.5 houdini (it does not seem to be an out of memory
>> issue). Looking at a few threads on the forum it seems that others have
>> experienced this too.. so currently our workarounds are :
>>
>> 1) to spit the simulation into chunks of columns and reading subsequent
>> chunks as passive collision objects, but this has the problem of getting
>> the walls to interact with each other properly,  i.e at the sides of
>> each column having no bricks to collide with means the cubes are free to
>> move without resistance
>>
>> 2) try houdini 11, hope the crashing goes away
>>
>> 3 ) or swap to the open source bullet implementation...  although so far
>> with this I find the wall can't self stand, and the bricks seems to push
>> each other away (its like they want to move away from each other)
>>
>> any DOPS guru's out there have any handy tricks up their sleeves..
>>
>> thanks
>>   Miles
>>
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-- 
Miles Green
Digital Artist, FX Lead TD, Guardians
T: +61 [0]2 9383 4928




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