Hi,

I've noticed something strange :
I've made a dynamic simulation with 115 objects consisting of 19000 polygons (I know I should used lowres proxy but it worked fine)

Then I've cached the sim using a file dop.
Now, when I play the simulation from the file dop and display it in the viewport from the dop network, it's really fast, but if I create a very simple sop network with just a dop import, fetching the geometry, it's much much slower.
I thought, ok it's the time to fetch the geometry, but if I render that as a bgeo sequence with a rop or file sop, and then read it with a file sop, it's a little faster, but still much slower than with the file dop.

Why is that ?
Isn't it in both cases reading geometry from files ? (.sim in the dop and .bgeo in the sop)
Something to do with ram caching ?

I was wondering how I could speed up my viewport renderings, I've recently changed my cpu for a quadcore, and thought, maybe a faster graphic card would help, but obviously in this case the graphic card is fine.

Thanks a lot

edit : just found about the cache sop, and I can now get a fast playback, however, it requires enormous amount of ram, not required in the dop network. So, still interested in how the dop network allows such a fast playback with not much ram.

The way I understand it is that the dops network is like the pops network in that the geometry is just a reference for generating the simulation data. Since the simulation is acting on the points of geometry you are provided a view from sop space, but sops is the only place where the geometry is “moving”.

Animation in sop space is actually a deformation and thus much more computationally intensive. It is were point/primitive data is actually being manipulated.

You can turn on the performance monitor and see exactly where your performance hit is occurring.

I've likely really butchered the explanation, but it works for me

I haven't used dops, but I think I read somewhere you can import the transformations onto objects. So it might make for faster play back if you could have 115 instances and apply just the dop transforms to those objects rather than bring the meshes into sop land…

Thanks for answering, importing the transforms only is indeed faster, but I've made a test where I start a blank new file, create a dop network and create a file dop in it, and import a cached simulation as .sim files, and the playback is very fast and it uses almost no ram.

In this case the file dop has to read all geometry from the sim files, but it's a lot faster in the viewport than a file sop reading the equivalent .bgeo.

I've noticed the file sop can load .sim files too, but it's slower than bgeo…

Another weird thing, when I import .sim files going from frame 1 to 50, first time I play it, I get nothing after frame 50, which is expected, but if I hit play again from the start, the simulation continues after… Have to do more test on this, but it's really strange.