[MAIN ISSUE] Materials Functionality is inconsistent and inflexible

[sliptonic]

Is there an existing issue for this?

• I have searched the existing issues

Full version info

any

Subproject(s) affected?

None

Problem description

this is a placeholder issue.

Materials is a broad requirement in many different workbenches. A more robust and integrated capability is needed that supports existing tools and allows us to develop more advanced features in the future.

Context:

https://forum.freecad.org/viewtopic.php?t=16714&sid=3ee17d7b50064496fa66255f0a46672c

https://ondsel.com/blog/freecad-needs-a-better-materials-system

https://forum.freecad.org/viewtopic.php?style=4&p=685834#p685834

Anything else?

No response

Code of Conduct

• I agree to follow this project's Code of Conduct

[luzpaz]

CC @davesrocketshop (just linking you to ticket 😉 )

[davesrocketshop]

1st PR submitted. From the pull request:

NOTE: This PR introduces a new dependency on yaml-cpp (https://github.com/jbeder/yaml-cpp). This is available through
apt on Debian based distributions, but the LibPack image will need to be updated for Windows builds

First PR for Issue #10174 - the Materials system update.

• The editor is minimally functional. You can save changes but may need to restart for them to take effect
• The API supports new and old methods of access. See the unit tests in src/Mod/Material/TestMaterialApp.py for examples
• Uses an updated .FCMat format. The old editor won't read the new files, but the new editor will still read the old files.
• Defaults to the old editor. This can be changed in the Material Preferences pane
• System materials are in the new format. You can still use the old format files by copying them to a separate folder and adding that as a custom folder in the Material Preferences pan
• Moves the preferences from FEM to a separate Materials section. This was submitted as a PR prior to 0.21 but that PR has been closed to avoid conflicts

[sliptonic]

Dave did a good breakdown of the work that needs to be done. I'm reproducing it here. A lot of these topics are already individual issues or should become issues at the right time but let's not swamp the tracker just yet.

Materials Core
- diff feature
- export inherited models
- internal APIs
- unit tests

Material libraries API
- support external libraries
- e.g. Web Services/DB/git
- API for add on workbenches

Material arrays
- Validation (no duplicate entries, for eg)
- Interpolation: in-between values

Materials Editor
- edit/save/load material cards

Materials diff viewer
- visualization of core diff function
- Possibly as part of editor and/or standalone

Embedded Materials
- Save materials with documents (optional)
- Create external material card from embedded material
- In-Document material card with no external file

Physical Materials
- add new property for physicl materials
- every Shape object would have an associated materials object
- embed in FC document where desired
- multi-materials

Appearance Materials
- Associate Material property with cards
- remove hard coded materials in favour of cards
- add texture(image) support

Apperance Preview
- Create more realistic preview for Materials UI
- related to Appearance/UI tickets

Arch migration
- Migrate Arch workbench to use new Materials
- thread on forum
FEM migration
- Migrate Arch workbench to use new Materials
- thread on forum

[davesrocketshop]

New PR #11138. Primarily editor enhancements to support arrays, but also improvements to the material save workflow. Numerous minor improvements