Assembly save mode=default vs mode=fused

[ZTThomasOberthanner]

My goal is to export objects into a stl-file. Afterwards these objects are processed using blender split by loose parts.

When reading the docs cadquery.Assembly.save it is possible to fuse all parts into a single one using mode=fused. But even using mode=default all objects are fused into a single part. Is this a bug or my misunderstanding?

These are 3 different assemblies, all made of two boxes:

import cadquery as cq

box = cq.Workplane().box(1, 1, 1)

assy_default = cq.Assembly(name="toplevel")
assy_default.add(box, name="box1")
assy_default.add(box, name="box2", loc=cq.Location((1, 0, 0)))
assy_default.save("boxes_default.stl", exportType='STL', mode='default')

assy_fused = cq.Assembly(name="toplevel")
assy_fused.add(box, name="box1", loc=cq.Location((0, 5, 0)))
assy_fused.add(box, name="box2", loc=cq.Location((1, 5, 0)))
assy_fused.save("boxes_fused.stl", exportType='STL', mode='fused')

assy_split = cq.Assembly(name="toplevel")
assy_split.add(box, name="box1", loc=cq.Location((0, 10, 0)))
assy_split.add(box, name="box2", loc=cq.Location((2, 10, 0)))
assy_split.save("boxes_split.stl", exportType='STL')

PS: I wanted to paste the output using CQ-editor, but got a ValueError: Unknown Format: STL

[jmwright]

For STL export the assembly is made into a single compound by calling toCompound() on it.

cadquery/changes.md

Line 74 in 6869dc6

* Added `Assembly.toCompound()` to enable proper assembly export to formats like STL [#726](https://github.com/CadQuery/cadquery/pull/726)

The notes at the top of the document here explain why we do this with STL files.

The fused mode was added mainly for STEP, which supports multiple parts/colors in the file.

[ZTThomasOberthanner]

thank you for the quick reply - I will create a pull request to add this information to the comments/documentation

[ZTThomasOberthanner]

#1458