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CAD tip CAD tip # 12237:

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Q - question

UnfoldRS - unfold 3D surfaces to 2D in AutoCAD.

A - answer Similar to Inventor (unfold, unwrap) or Fusion 360, also AutoCAD can unfold some types of unfoldable 3D objects/surfaces to 2D representation, e.g. for forming sheetmetal or glueing paper, textile or cardboard.

The freeware LISP application UnfoldRS can unfold ruled surfaces, i.e. objects created by the RULESURF command from border curves of any type. Typical examples are: conical surfaces - reducers between ducts of different diameter, transitions (transforms) circle-ellipse or ellipse-rectangle, facade building elements formed by two 3D splines, etc.

The rule surface must be generated in the legacy Polyline mode, i.e. with the MESHTYPE=0 setting. The precision of the surface (and then of its unfold) depends on the setting of the SURFTAB1 variable.

The result of the unfold is a planar representation of the object made of a group of 3D Faces and a group of outline curves circumventing the shape of the unfold (e.g. to be cut from sheetmetal).

You can download the UnfoldRS utility from Download, load it into your AutoCAD with APPLOAD and run by typing the UNFOLDRS command. Choose the Polyline mode and select a previously created rulesurf object. Enter the layer name for the unfold.

Unfolds cannot be used on twisted surfaces - you can avoid twits by rotating or 2D/3D mirroring of one of the source border curves. In the Face mode, you can also unfold individual 3D faces, but they must be created in the same way as in an exploded ruled surface.

Sample drawing is available in tbe block library.

Usage of the UnfoldRS utility:

This is a purely geometrical unfolding, without respecting material properties. Use Autodesk Inventor or Fusion 360 for advanced unfolding of 3D models, including K-Factor, etc. Similar to UnfoldSurf.

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12.5.2019    39903×   FAQ  
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applies to: AutoCAD ·

See also:
Tip 12416:How to export DXF outline of unfolded sheetmetal in Fusion 360, with no bending lines.
Tip 12411:How to wrap text on a cylinder or a general 3D surface in Fusion 360?
Tip 12392:Export unfolds of sheetmetal parts to DXF - parameters for iLogic and VBA
Tip 12365:How to show color print (sketch) also on the sheetmetal flat pattern?
Tip 11946:How to find net surface area (sans holes) of an unfolded sheetmetal part in Fusion 360?

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