Alternate OpenSCAD Importer

NOTICES

Functions such as PrismaticToroid require facilities in the FreeCAD version 0.20 of Part

Installation

It can be installed via the Addon Manager (from Tools menu)

Alternative Installation

Clone into FreeCAD's Mod directory see https://wiki.freecadweb.org/Installing_more_workbenches

• Change to FreeCAD Mod directory
• git clone https://github.com/KeithSloan/OpenSCAD_Alt_Import.git

• Start/Restart FreeCAD

Now supports

The idea to allow hybrid development ( FreeCAD and OpenSCAD )

• Importing SCAD files as FreeCAD Objects.

• Edit SCADObjects with an external editor

• Import of Minkowski request with a Sphere as a Part::Offset

• Import of Minkowski request with a Cylinder as Part::Offset & Part::Fillet

• Matt Considine's improvements utilizing python EZdxf library

  • OpenSCAD DXF import
  • DXF importer
  • Now supports DXF files with INSERT tag.

New OpenSCAD DXF importer

• For test files see directory testDXFfiles
• Test of test files see Macro Macros/testSCAD_DXFfile.FCMacro ( Copy to FreeCAD Macro's directory )
• If problems please report and drop back to main FreeCAD importer.

• Note: If the scad file imports external files use one of

  New Importer : SCAD (importCSG) New Importer : SCADFileObject

  New Importer : SCADObject currently does not support import of external files

External Editor

For a number of years OpenSCAD has supported an External Editor

To use an external editor for SCADObjects

You need to add a parameter to the OpenSCAD workbench

  FreeCAD | Tools | Edit parameters

  Group : Base App
      Preferences
         Mod
            OpenSCAD
                externalEditor
                    Text : <path to editor > 
                    e.g. Text /usr/local/bin/code

Use

With the workbench installed when opening a CSG or SCAD File with

    FreeCAD | File | Open 

the user will be prompted with which importer to use.

• SCAD (ImportCSG) : Uses OpenSCAD to convert SCAD file to CSG and then import as FreeCAD Brep Objects
• SCADFileObject (ImportFileSCAD) : Imports as a FreeCAD SCADObject. Source remains the original file.

• SCADObject (ImportSCAD) : File is copied into FreeCAD and saved with FreeCAD file.

  ImportCSG - Import CSG or SCAD file

  Changes from standard Importer

• Minkowski

Minkowski requests where the second object is a Sphere or Cyclinder is handled as follows

Sphere

$fn=50;
minkowski()
  {
    cube([10,10,1]);
    sphere(1);
  }

Produces a suitable Part::Offset of the first Object i.e with rounded edges.

Cylinder

$fn=50;
minkowski()
  {
    cube([10,10,1]);
    cylinder(r=2,h=1);
  }

Produces an Part::Fillet of a suitable Part::Offset of the first Object, fillet radius that of the cylinder.

Where the FreeCAD has an editable Fillet

• Hull A limited number of hull requests are converted to BREP equivalents

        - Collinear cylinders & cones
        - Two Spheres
        - Two Parallel Cylinders of equal length, orthogonaly displaced.
  
     others are dealt with as per standard importer i.e passed to OpenSCAD
     executable to create a Mesh

  SCADFileObject

  Created from imported File - Only file reference is saved with the FreeCAD Document

  Properties

  

  • edit : Toggling will invoke the external editor.
  • execute : Will process the SCAD source ( Object or File ) to create a the Objects Shape.
  • message : Any error messages from OpenSCAD.
  • mode : Brep or Mesh.
  • timeout : time out value for operations passed to OpenSCAD.
  • source : Source file name
  • source File : Path to source file (ImportFileSCAD)

  Brep Mode

  OpenSCAD is used to create a CSG version that is then imported into a Work document as FreeCAD Objects. The Work document is processed to create/update the SCADObjects Shape as a Single Part::Compound

  Brep Propertries

  • fnmax : Sets the fnmax parameter for the CSG import of this Object
  • keep_work : Option to save or close the Work document

  Mesh Mode

  OpenSCAD is used to create a STL version that is imported to create/update the SCADObjects Shape.

  Mesh Properties

  • mesh_recombine : For future option

  SCADObjects

  Created from imported file - Saved using JSON with the FreeCAD document

  For creating FreeCAD objects from SCAD source. Should avoid SCAD files that depend on other files i.e. Have use or include statements.

  Properties : See SCADFileObjects properties.

  Using SCADObjects and OpenSCAD external editor.

  Using a combination of an external editor for SCADObjects and having OpenSCAD set up for an external editor allows.

  • One to edit the source for FreeCAD OpenSCAD objects

  • Preview any changes in a OpenSCAD Preview window

  • When happy with source definition

  • Save SCAD Source file

  • Toggle SCADObjects - execute property to have changes brought into FreeCAD

Example Screenshot.

Advantage of using an external editor that is also setup for OpenSCAD

The performance of OpenSCAD Preview has been significantly improved since Feb 2022

OpenSCAD 3D rendering just got an order of magnitude faster

Thanks to FreeCAD Users

• mconsidine
• wmayer
• chennes
• edwilliams16
• onekk