Skeleton Planes - how to?

[alex::freecad]

Hi,

I read through almost all tutorials, found the nice explanation on how to use scalabe design in the bearing holder tutorial.
But it is unclear to me how to get the skeleton planes into the model.
Is there a way I can get 'construction objects' in the part designer?

Background: i try to model a multipart object for later use in FEM calculations.
One basic structure (attached) is an arch combination which will be extruded.
I have reference positions (in the sketch the 325mm distance points), where other objects will later be added (in 3D, not in te sketch).
So I guess I would need to get these positions as referenceable edges in the 3D model in order to be able to use it in other sketches as reference.

Was this clear? I'm not sure. Sorry...

Alex

[alex::freecad]

I could use another sketch, draw 2 lines and then back in part designer make a ruled surface.
however, back in the first sketch I'm not able to select the plane as external geometry.
What am I doing wrong?

[jmaustpc]

Is there a way I can get 'construction objects' in the part designer?

Just insert any normal object, select it and then click on the icon for toggle construction mode in the tool bar.

See the FreeCAD wiki here for information specific to construction mode

http://freecadweb.org/wiki/index.php?ti ... uctionMode


see the FreeCAD wiki here for a quick explanation on Sketcher wb

http://freecadweb.org/wiki/index.php?ti ... _Workbench

This is above is a reply to your first post.... you have posted again while I was typing.

External geometry is a construction line that is linked to a geometric part of the solid to which the current sketch has been mapped. For it to work you must have your sketch mapped to the face of a solid......from memory it does not not work on faces of surfaces, they have to be solids, even though the sketch can be mapped to a face/surface.

search the wiki for "external geometry" and you will find a good explanation of the tool. If you can't find the page let me know and I will post the link....but you should find most basic things in the wiki by using its search box.

Jim

[ickby]

as noted on top of the wiki page the bearing holder tutorial is for a experimental freecad version and the features it describes are currently not availabe.

[alex::freecad]

Just insert any normal object, select it and then click on the icon for toggle construction mode in the tool bar.

yes, in the sketcher, this is clear to me and I have already used it.
But how in the part workbench?

suppose I have a 3D solid which I will mesh later one (so it should be one part).
The 3D part however will be constructed using several skeleton planes used in several sketchers. (just like the ones here: http://www.freecadweb.org/wiki/index.ph ... Tutorial_I).

So the question is how to get (in Part workbench) several planes to which I can map sketches and use the edges as external reference in the sketches, but later not beeing part of the 3D model for meshing....

Alex

[alex::freecad]

as noted on top of the wiki page the bearing holder tutorial is for a experimental freecad version and the features it describes are currently not availabe.

I'm running:
OS: Debian GNU/Linux 7.6 (wheezy)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.15.3967 (Git)
Branch: master
Hash: cef2c1bc8c0f342b86acec1704e8259c4948462a
Python version: 2.7.3
Qt version: 4.8.2
Coin version: 3.1.3
SoQt version: 1.5.0
OCC version: 6.5.2

so the features described should be included - not?

[ickby]

the only way to get these features is to compile FreeCAD from this special development branch: http://sourceforge.net/p/free-cad/code/ ... ly/~/tree/

and I do not recommend to build this branch as it is not realy in a workable state right now. Also the files you create with this branch may be unusable later

[alex::freecad]

as had been said above:
external seems to work on surfaces of SOLIDS.

this leads me to the conlusion that the planes in the bearing holder tutorial must be solids -> not planes but thin cubes with nonzero thickness - right?

[ickby]

no, the planes are planes but the implementation is very different. so you can't compare it to current bahaviour

[alex::freecad]

ok. so no construction planes yet.

It should however be possible to start with cubes having the faces representig the basic dimension, then map the sketches on those faces and relate to the edges, not?
In this way it should be possible to change the basic cube's size later, and the rest sould follow. Or am I still missunderstanding the accessible features?