I joined two cubes to one cube.
and I used subdivision modifier to make the object smooth.
But the object divided into two parts.
How can I use subdivision modifier to joined object without dividing the object?
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Sign up to join this communityI joined two cubes to one cube.
and I used subdivision modifier to make the object smooth.
But the object divided into two parts.
How can I use subdivision modifier to joined object without dividing the object?
Once you've joined the two cubes the geometry of both cubes still exists. With your joined cubes selected go into Edit Mode (tab) and Select > All:
Then Mesh > Merge > by Distance. If the faces of the two cubes are close enough then this will merge them (and each of their four vertices) into one. There will still be one face inside that you probably don't want, select it and delete it:
With your Subdivision Surface modifier it should now look pretty much like this:
Join didn't change the meshes. If you want the two cubes to be replaced by a single object, you can select that object
go to edit mode
type A to select all
type M to bring up the merge menu.
Select by distance from the popup.
NOTE: that only works because your two cubes are very close together. If they were further apart you would need a different technique.
Now you'll have one object but it will have an interior face, because merging the vertices didn't delete the extra face. While still in edit mode:
type ALT–A to deselect everything
go to the select menu and select Select All by Trait → Interior Faces
type X to bring up the delete menu.
Select faces from the menu.
You should now have an object that looks like this in wireframe mode:
Now the modifier will work as expected: