Can anyone tell me the best way to creat an object, then cut it into pieces, but
hold it together until hit by another object. This is done in the dynamics turorial with the vase. But it gives no clue as to creating the broken pieces for the vase and hold them together until you destroy it. The dynamic tutorial was very helpful but left me wanting more.

First, each of the pieces must be fully enclosed, watertight, manifold, etc. In other words, the pieces should define a volume and not have a single hole or unshared point/edge.
Each of the pieces are to have completely unshared points with neighbouring pieces.

Once that is assured, then you are only two SOPs away from defining each piece as a DOPs object or what some refer to as a “dobject” to not confuse DOPs objects with regular objects.

Next append a Connectivity SOP. This SOP builds either a point (default) or primitive (my default) attribute that simply puts a number unique to each piece in your data. For example, if you had three distinct pieces and your attribute was called “piece” then all the primitives in the first piece would have the attribute value 0 for piece, the second would have it's prims set to 1 and the third would have 2 for all it's primitives.

Finally append a Partition SOP. This SOP works hand in hand with the Connectivity SOP. If for example the attribute was called “piece”, then you would use the following expression to build the appropriate groups for either the RBD Fractured Object DOP or the RBD Glue Object DOP which by the way take primitive groups and turn them in to DOP objects:

my_pieces_$PIECE

Notice that the geometry attribute bouond on the geometry is raised from lower caps to upper caps. This is just one of those Houdini things that you just have to know.

Now you can fetch this Partition SOP in to DOPs with the fractured or glue object DOPs and you should have a dobject for each group.

Notice that the geometry attribute bouond on the geometry is raised from lower caps to upper caps. This is just one of those Houdini things that you just have to know.

BTW, the rule is defined in the AttribCreate SOP. You can always find out what the mapping is by middle-clicking on the SOP operator in the network editor and noting the conversion in the pop up under Custom Variable Mappings.

There's a smashing rabbit example somewhere that does the same thing but has all the sops in it that make the chunks. It was posted up on the beta forum after a request for tutorials, have a hunt for that.
It basically uses spheres and the cookie sop to cut up the geometry.

Thanks everyone for your help. I can not find the smashing rabbit though. I looked at almost every file on the exchange.

It's not on exchange it's in the Beta forum, the H8 early access one. Maybe you can't access it.

try this link i think it might be in here

http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&t=4427&highlight=dops [sidefx.com]

Thanks Simon for the link. I would have never found it. There is great stuff and just what I was looking for there. Houdini is awsome. And the forum and people that are part of it are great. Thanks Jeff and Edward as well. Your information helps out a lot.

There is also a Breaking Rock example file that comes with Houdini 8 (linked from one of the help cards, probably RBD Glue Object) that includes the SOPs for breaking up the rock. Probably very similar to the bunny file, but it always helps to have more examples…

Mark

I have been messing around with this breaking objects now as well as breaking objects. At ODD Force i have found a tutorial on how to simulate breaking ice. With the little bit i have experimented with this and the dynamics tutorial, it seems you can break objects via this tutorial, assign groups to pieces of the ice. Then creat a DOPs network and it should work. I have not spent much time on it, but the little i did showed great promise.