How to hollow out this shape

[fatbeard]

I have a shape like this:

Screenshot from 2021-09-20 15-10-06.png (143.52 KiB) Viewed 1816 times

and want to make it hollow with a 1mm wall thickness.
The "make a thick solid" tool does not work: it reports Thickness not possible on selected faces/edges. , Error, Select an edge, face, or body from an active body. (with the body selected) or BRep_API: command not done depending on the item(s) selected but does not do anything else...

Surely I am doing something wrong, but can not find out what: the error messages are, ehrmm, not very helpful...

I even simplified the block, reducing it to only flat surfaces and a single padding, only to get the same list of errors.

OS: Linux Mint 20 (X-Cinnamon/cinnamon)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.
Build type: Release
Branch: unknown
Hash: 0d9536ed3e8c7f40197b5606e1b7873625e1d6fe
Python version: 3.8.10
Qt version: 5.12.8
Coin version: 4.0.0
OCC version: 7.5.2
Locale: English/United States (en_US)

[papyblaise]

you did not specify which faces to open, which to keep

[openBrain]

Thickness feature doesn't work this way. It works as if you were hollowing the solid by "digging in" it from a face (several faces). And you basically select this(these) face(s). You can't hollow a plain solid that shall keep it's external envelope identical at the end.

[fatbeard]

Thanks.
The picture that @papyblaise showed was almost correct (the comment was spot on ), @openBrain nailed it.
.I did it before, but got a little confused juggling 4 different CAD programs at once...

Screenshot from 2021-09-20 16-47-14.png (120.51 KiB) Viewed 1731 times

.
Next challenge: webbing, magnet holder and an attached lid...

[kisolre]

Next challenge:

Keep us updated on your progress

[domad]

Greetings to the Community!
.... since it resembles a bottle, I am attaching an example of a workflow that allows you to empty it (entirely) maintaining a thickness of 1 mm, then create the neck (which could be threaded) finally open literally to show the internal part with the edges connected like the outside.

[fatbeard]

Nice bottle! But I wanted to avoid subtracting two solids...
Just a quick update on the status:
.

Screenshot from 2021-09-21 14-56-30.png (136.29 KiB) Viewed 1565 times

.
I know, the lid hinge is not in the right place: when closed, there will be a 1mm ridge. Working on that.
I also have to route an extremely densely packed 12-layer PCB with lots of constraints by the end of the week, so be patient.

[papyblaise]

voilà un joli bidon