FreeCad, Blender, and SweetHome3D

[marcin_ose]

We are using FreeCAD, Blender BIM, and SweetHome3D to take advantage of each tool in an architecture workflow. FreeCAD is good for technical design and part trees that can be exported automatically into Bills of Materials. Blender has BIM functionality for export in a universally readable open source architecture format. And SweetHome is great for ease of use and visualization, for both concept and technically-correct design.

This means that if we can interoperate seamlessly between the 3 open source tools, we can establish a robust, scalable, open source and collaborative workflow.

I observed that direct export from SweetHome3D to FreeCAD results in objects 10-20x smaller - see Google Presentation page at https://wiki.opensourceecology.org/wiki ... perability. So it is useful to use Blender for scaling the mesh file, then importing to FreeCAD, and turning back into a solid . Blender is good at scaling through its properties dialog, which allow numerical input. Does anyone else use SweetHome3D exports in FreeCAD, and know the correct scaling factor?

Marcin

[Puybaret]

Thanks for explaining your workflow.

As lengths and coordinates in Sweet Home 3D are internally expressed in centimeters, these values are exported to OBJ format in the same unit. Unfortunately that file format doesn’t specify the unit of the coordinates it contains (DAE format has a [font=courier new]unit[/font] element to specify that), and that leads to variable interpretations of these numbers according to each software.
If you want to work in meters in Blender, you should scale imported OBJ files exported from Sweet Home 3D to 0.01. If you prefer inches you should scale them to 0,393701.
But isn’t FreeCAD able to directly scale imported OBJ files? That would avoid using Blender just to rescale them.

[UbuntuBirdy]

In FreeCADs Draft-Workbench you can scale any imported object.

[marcin_ose]

In FreeCAD, one would first need to first Create shape from mesh..., and then scale it in Draft Workbench. For details of how to do this, see Lesson 1 and Tutorial 24 at https://wiki.opensourceecology.org/wiki ... Tutorial_1.

For the scale factor, I found that the scale factor from SweetHome3D to FreeCAD is exactly 10x by taking the box in SweetHome3D (3'x3'x3'), which appeared as 3.6" in FreeCAD. This result is consistent for other objects.