Houdini Group Syntax

Confused about Group Syntax? Wondering how to AND operation in Group Syntax?

Say, I am using a Blast node to delete some points in SOP context, and want to:

• delete the points which "name" attrs are "inside", I can use this syntax:

@name=inside

• delete the points which "height" attrs are greater than 10, I can use this syntax:

@height>10

It is simple if the condition is only one, but how about combining the two above?

• like, delete the points which "name" attrs are "inside" AND "height" attrs are greater than 10? Use this syntax:

@name=inside ^!@height>10

Does it look confusing? Let me explain.

• The ^ is to remove some points from the results of preceding pattern (the preceding pattern is @name=inside), and what are the points it will remove from the preceding pattern?

• The points are those matching this !@height>10 pattern, which "height" attrs are less or equal to 10. So once these points are removed. We will get

• The final points matching both @name=inside AND @height>10.

• So ^! combination means "remove those that are not ... ".

Does it sound good now?