extrude from curved surface / coating

[alex::freecad]

Hi.
suppose we'd have a model of lets say an airfoil (curved 3d body).
Could I 'coat' / extrude the geometry e.g. by 1mm in normal direction everywhere?
Could be in python or via interface...

Background: when laminating an airfoil, one uses a e.g. foam kernel and possibly two half shells.
The half shells have the geometry of the final airfoil, the foam kernel should have final geometry minus the fibre/expoy thickness.

Thx
Alex

[NormandC]

Hello Alex,

I think Part Offset is what you are looking for. It works on faces as well as shells or solids.

[alex::freecad]

I tested the part offset. Everything is fine withe standard objects like cones etc.
However, using the fin example from here (which would correspond to my usecase):
https://forum.freecadweb.org/viewtopic.php?t=5295

I get the error 'Input Error GeomBSpline surface'

I tried to convert the fins loft to shell and solid, but the underlying BSpline and error of course stay the same..
Any hints?


OS: Debian GNU/Linux 8.6 (jessie)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.10101 (Git)
Build type: Release
Branch: master
Hash: 99fa203f323927b0dd027420d4421b577b7420c3
Python version: 2.7.9
Qt version: 4.8.6
Coin version: 4.0.0a
OCC version: 6.7.0