Hi guys, very nice to meet you here.
I'm a beginner with Houdini Apprentice 16.0.600. And I started using Boolean tool last night.
I set a Cube as object A and a Sphere as object B. Boolean operation is A-B. But I can't see the result that should happen.
Very appreciated that you can point out where I was wrong. Thank you very much.

Try changing the Sphere node's Primitive Type parameter to Polygon or Polygon Mesh. I think the Boolean node only works with polygon primitives.

ndickson
Try changing the Sphere node's Primitive Type parameter to Polygon or Polygon Mesh. I think the Boolean node only works with polygon primitives.

I tried what you said just now. It works really well. Thank you very much bro. And by the way, can you tell me more about the difference between Primitive,Polygon,Polygon Mesh and Mesh. Very appreciated. Have a nice day my friend.

XanaduArt
can you tell me more about the difference between Primitive,Polygon,Polygon Mesh and Mesh

In addition to polygons, Houdini has quite a few other primitive types, including: tetrahedra, NURBS curves, Bezier curves, NURBS surfaces, Bezier surfaces, bilinear meshes, volumes, VDBs, spheres, tubes, circles, metaballs, metasuperquadrics, packed geometry primitives, packed disk primitives, packed fragment primitives, packed Alembic primitives, packed agent primitives, etc.

Primitive spheres are less memory intensive than polygon spheres, but not many operations can work with them directly, so unless you just want spheres as they are, they won't be very useful. Even some cases where you might just want spheres, disconnected points with a pscale attribute often suffice and are much less memory intensive even than sphere primitives. They're most often used for just visualizing spheres in the viewport.

Bilinear mesh primitives, (what the “Mesh” option generates), are just a single-primitive representation of a grid of quads. Not many operations support them, either.

The “Polygon” option generates a polygon sphere of triangles that are as close as possible to equilateral, with a topology based on dividing an icosahedron. When modelling, however, people often want a polygon sphere that's effectively a grid of quads, so the “Polygon Mesh” option gives all polygons, but with a grid topology that's the similar to the “Mesh” option.

XanaduArt
Have a nice day my friend.

You too!