feature: general initial value and body source, to be tested

[qingfeng.xia]

Rebase after stop for a while is kind of disaster to me . I may add a bit in-source documentation then I hope to PR.

BodyAccelation is a quite useful constraint. it can let FEA simulate linear acceleration, centrifuglal. It modelled after Ansys Mechanical

https://studentcommunity.ansys.com/thre ... ting-body/
Displacement, Velocity and Acceleration make the complete constraint for transient FEA.

Would "Acceleration", instead of "BodyAccelation" make a better name? it a more general term for self-weight.

pressure initial value is only needed in CFD, on par with Initial Velocity.

[qingfeng.xia]

If you think necessary, A in-source documentation should be added to the class ConstraintGeneric to outline how to use this class, or add those doc into freecad wiki directly?

I prefere in source.

But more important would be a real use of one of the constraints. ATM there are two new constraints which are new but not used. My be someone does implement them as real constraints. These ones which are based on the generic constraint would than not needed anymore.

Or do you use them in any solver not included in FEM already?

I topped up one more commit, and sent PR to your branch, add in source doc, how to use it.

The last bit of demo, how to collect info from those generic constraint, will be ready soon, I will paste some piece of code snippet in Cfd module.

Basicaly, there is a Python dict "Settings" property contains all the value information, as usual, geometry selection can be get from "References" list property.

[chrisb]

It would be great if it wasn't only possible to mark the whole document, but also all other elements or containers in the tree.

[qingfeng.xia]

I can add more document, in that case, doc will be much long than the code, what is why I think it deserves a page. I will do another top up tomorrow thank you

[qingfeng.xia]

I topped up 2 commits on documentation, one commit renaming,
see PR to your branch. https://github.com/berndhahnebach/FreeCAD_bhb/pull/78

There is one file, with your in source notes,
femobjects/ConstraintGenericDefaults.py
I leave it to you to further clean it before PR to master.

I run out my time this summer, and I have no time to impl any new feature for FEM this year, may be this Xmas. I will update my Cfd module after FreeCAD 0.20 release.

If you think necessary, A in-source documentation should be added to the class ConstraintGeneric to outline how to use this class, or add those doc into freecad wiki directly?

I prefer in source.

But more important would be a real use of one of the constraints. ATM there are two new constraints which are new but not used. My be someone does implement them as real constraints. These ones which are based on the generic constraint would than not needed anymore.

Or do you use them in any solver not included in FEM already?