modo: subtract operation

the items to be used with Boolean operation should be in different Meshes.

1. create a box in mesh1
2. create a sphere in mesh2 (n key creates new mesh. ctrl+left-click on sphere icon in basic tab of tools menu creates sphere)
3. being in Items mode, left-click on the box and shift+left-click on the sphere to select both items.
4. select Tools menu -> mesh edit -> commands panel -> Boolean, this displays a boolean dialog box. In the dialog box, select Operation as Subtract and Drive mesh as Last Selected. click the ok button.
5. As the box is the first selected and sphere is the last selected, sphere gets subtracted from other selected items, leaving a hole in the box.

Modo subtract operation works only when mesh1 and mesh2 items are closed surfaces.If either of them is not closed then subtract operation fails with a dialog mentioning the mesh name which is not closed. In such case to find the holes select ctrl + boundary (polygon mode button), which displays all the holes on the mesh. If a mesh is closed it would be continuous, it won't have any boundaries. If a mesh has boundary then it's open. Open mesh can't get printed on 3d printers.

The subtract operation results in new meshes. When a subtract operation divides an item into two, the divided parts might be open. If the subtract operation results in open parts, subtract operation ends with a message informing the new parts are open.

When a subtract operation divides an item into two, the split parts still get selected as a single item in item mode. To individually select either part of the divided item, change to polygon mode and double click on the part you want to select then copy and paste it into a new mesh.

I tried to do the same operation using Mesh Fusion, but fusion subtraction is working using subdivision algorithms, where a new subd shape of the box is created and sphere got subtracted from the newly created subd shape. Because of this I didn't like Mesh Fusion. In fusion the item being subtracted is attached to the top brown circle. The source item is attached to the lower gray circle. in fusion i used the option "subtract others from first selected".

Modo is hanging while doing subtract operation in items mode. Replace step 3 with the below steps:

1. being in Polygons mode, in Item list tab,  left-click on mesh1 and shift+left-click on mesh2.
2. in 3d view, double click on mesh1 to select all the mesh1 polygons and double click on mesh2 to select all the mesh2 polygons