Getting maximum value of attribute

[simonj]

Hi!

I'm a little bit stuck.

I have a RBD fractured object which contains 4 diffent groups of geometry. Before I send in the data to be processed in a custom Force VOP I'd like to find the piece with the maximum mass in the groups, and return this mass.

So it looks like this:

obj1 - mass: 32

obj2 - mass: 210

obj3 - mass: 150

obj4 - mass: 80

In a custom parameter in my Force VOP I want to have an expression that would loop through/search the different groups and return the mass of the group with the highest mass: 210.

Come to think of it, I have no good way of doing this in SOPs either..

Can anyone help me out?

Cheers,

Simon J

[johner]

Hi!

I'm a little bit stuck.

I have a RBD fractured object which contains 4 diffent groups of geometry. Before I send in the data to be processed in a custom Force VOP I'd like to find the piece with the maximum mass in the groups, and return this mass.

So it looks like this:

obj1 - mass: 32

obj2 - mass: 210

obj3 - mass: 150

obj4 - mass: 80

In a custom parameter in my Force VOP I want to have an expression that would loop through/search the different groups and return the mass of the group with the highest mass: 210.

This is the sort of thing that's much easier in Python. So put a Python expression into the parameter of the Force VOP and put something like this in it:

max(p.findSubData("Position").options().field("mass") for p in pwd().simulation().objects())

The only problem is that HOM doesn't yet support DOP Object groups, so at the moment you have to get trickier if you want to limit this expression to only a certain group of objects.

Come to think of it, I have no good way of doing this in SOPs either..

Some version AttributePromote with "Promotion Method" set to "Maximum" will often do the trick.

[simonj]

This is the sort of thing that's much easier in Python. So put a Python expre...

Thanks man, it worked great.

[johner]

Thanks man, it worked great.

Sure thing. One more quick thought: you can actually get around the no groups in HOM problem a bit if all the objects you care about were created by the same DOP node (say, a RBD Fractured Object). If the name of the node that creates the pieces is named "obj" for example, you could write:

max(p.findSubData("Position").options().field("mass") for p in node("../obj").createdObjects())

and that would restrict the expression to only those objects created by that node. Groups are still the better way to go once HOM support them, but this might be a good workaround. Also, if for some reason you need the mass to show up on the first frame, checking "Solve on Creation Frame" will tell DOPs to do the volume/mass calculations as soon as the objects are created.