Baking Simulations

[wreath]

Hi, how can i bake dynamic simulations? writing and saving all sims are cost too much hdd space, i need to bake it thanks..

[old school]

To dump out the geometry, you need to put down an object and use an Object Merge SOP pointed at the DOP sim network. Then follow this up with a ROP Output SOP to save the resultant geometry out to disk.

If you built your sim from the shelf, then the object(s) with the proper DOP Import nodes and Object merge SOPs are already built for you. Just append the ROP Output SOP.

[wreath]

Actually i can't tell my problem well, for example; i have a bouncing ball and sim files for reading the bounce simulation but i want to translate simulation to keyframes(bouncing ball's movements) like animation not simulation which needs to be read from hdd, i dont know is it possible in Houdini but i hope.

[wreath]

Still waiting

[symek]

Let's assume that in Houdini everything is possible, ok? (Perhaps also that rare thing that something is not possible ).

Ok, jokes aside please. Seriously, this is possible in a number if ways among which using Dynamic CHOP is perhaps the easiest. You have example of using this node in Help. Simply add it to any CHOP network and press ? button on its parameter tab.

hope this helps,

sy.

Edited February 3, 2008 by SYmek

[wreath]

SYmek thanks i checked it out and tried 10 times but still can't bake, uploading test scene file can you please analyse whats wrong with it?

dynamic_chop.hipnc

[symek]

On the Dynamic CHOP change the parameter called "Method" from "Dynamic" to "Cached" and then press Update button. Press "H" key on Motion View to home your view. You should see number of curves.

This way you cached all simulation. "Dynamic" method keeps only the current frame value. From that you can delete channels you don't need and export them with Export CHOP.

Is this solve your problem?

cheers,

sy.

[wreath]

SYmek, i switched to cached and pressed update it calculated and box's channels turned to orange but rbd box is not moving anymore?! i really feel dumb

[wreath]

OOh it's ok ,i get the movement again but in this time box fallling under the surface??!

uploaded latest scene

dynamic_chop.hipnc

[symek]

I'm guessing you applied these channels to object level transformations. Since you're animating the origin effectively and your relative transformations starts and end at 0, your object's origin finishes at 0 -> object is underground.

If you're after applying simulation from proxy object in DOPs to another (heavy geometry) object, you can do this without CHOPS but with DOP Import SOP - in the same way as Shelf tools do this for you. In fact with DOPImportSOP you can apply simulation to any, even completely different objects as long as primitive groups match.

The way with CHOPs lets you for example export transformation data, plot it to a channels, filter or postprocess it. But they are local transformations. So depending on what you want to achieve you can use Math CHOP to shift ty channel, or add CHOPS's channels to existing one with chop() expression.

Edited February 3, 2008 by SYmek

[wreath]

Thanks a lot SYmek i'm working on this.

Edited February 3, 2008 by wreath