Hi all,

In the blast sop group parameter, I say if myAttrib is greater than five OR myOtherAttrib is equal to “test”:

@myAttrib>5, @myOtherAttrib=“test”

What is the syntax for performing an ‘and’ operation?

I don't think there is specifically AND operator , but as there is ^(except) and !(not)

you can do :
@myAttrib>5 ^!@myOtherAttrib=“test”
in other words group if myAttrib is greater than 5 except if myOtherAttrib not equals “test”
so that would mean if myAttrib is greater than 5 and myOtherAttrib equals “test”

and btw. for OR use just space, comas are not allowed

Great thanks. A little tough to read, but it works just fine for two conditions. Thanks!

My guess is that this doesn't work if you want to add a third ‘and’ condition, right?

Why wouldn't it?

Well it doesn't seem to work with groups. If I have three groups that represent P.x>0, P.y>0, P.z>0:

xpos ^!ypos ^!zpos

is not equal to:

@P.x>0 ^!@P.y>0 ^!@P.z>0

Is Houdini evaluating things differently when I'm listing groups? If I just have two clauses, it works fine. The addition of the third is where it diverges.

Note, just corrected an error in the .hip

it looks like it evaluates the pattern for groups incorrectly (bug?)
the result with attribute ad-hoc groups seems to be correct though

remember you can always use Group SOP/Combine tab to do more complex logic using both groups and ad-hoc groups

Totally, just trying to streamline my larger setups and use as few nodes as possible

I'll submit the group eval as a possible bug.

Thanks!

Btw the Group SOP's Expression evaluation is extremely slow compared to Wrangle SOPs. So if you can do it using VEX, you would see a much better performance if you care about that.

For anyone looking for a numeric replacement for && (e.g. selecting points between two values):

Group syntax uses '-' in the following manner:

@P.x = -0.05 - 0.05

(This will select everything having a position along x between -0.05 and 0.05.)