...add a circular hole in a body?
Offset
Turn into Circle
Move (M)
Shift-drag (resize)
Repeat on the other side
Hole
..add a circle across multi-face?
Add vertices at centers (Shift-V)
Add straight edges (Shift-E)
Add last edge (Shift-E)
Select loop (Shift-click)
Turn into Circle
Move (M)
....create a smooth curved tube?
Method 1
Pop-out (P)
Set distance (click)
Set angle (click)
Pop-out (P)
Fix (X)
Select edge chains (including fixed)
Set smoothen strength
Smoothen all chains
Unfix (Shift-X)
Move (M)
Fix (X)
Select edge chains (including fixed)
Smoothen
Copy Body
Set move distance (click)
Set rotate angle (click)
Bridge
Method 2 (alternative)
Select all faces (Shift-click)
Copy body (Ctrl-C)
Set angle (click)
Scale dimension (click)
Select edge chains (including fixed)
Set smoothen strength
Smoothen all chains
Unfix (Shift-X)
Move (M)
Fix (X)
Select edge chains (including fixed)
Smoothen
Copy Body
Set move distance (click)
Set rotate angle (click)
Bridge
...apply smoothness?
Move (M)
Pop-out (P)
Repeat...
Hide edges (W) and faces (R)
Fix all vertices (X)
Select all edge chains (Shift-click)
Smoothen
Repeat with edge loops
...soften sharp edges?
Pop-out (P)
Fix loop (Shift-click & X)
Fix outer faces (X)
Delete edges
Delete vertices
Repeat on opposite side
Use the "2" shortcut to delete vertices
Smoothen
...simulate a wide fillet on a junction?
Add vertices at edge fraction (Shift-V)
Add straight edges (Shift-E)
Repeat
Smoothen selected edge pairs
Delete vertex
Add straight edges (Shift-E)
Fix edges (X)
Smoothen
...round a cylindrical shape?
Rounding on one side
Pop-out (P)
Delete edges
Delete vertices (2)
Smoothen
Rounding on both sides
Add vertices at centers (Shift-V)
Add edges (E)
Circle
Fix loop (Shift-click and X)
Fix faces (X)
Select chains
Smoothen
...improve display of continuity?
Beware of triangulation artifacts! Not actual surface quality issues. Increasing the triangulation size removes them.
