“Duct Guardian” is a sheet ventilation fitting parametric layouts calculator. Calculates HVAC flat (unfolded) sheet development of ducts, rectangle to round transitions, cylinders, cones, elbows, etc.

Some common fittings:  Square to round, Radius branch, Radius offset, Cylinder, Cone:



“DG Nest”, is the best buy True Shape Automatic Nesting software on the market.