# FreeCAD BIM development news - April 2019
Hi!
Here we are for one more monthly report about what happened this month
around the development of [BIM
tools](https://github.com/yorikvanhavre/BIM_Workbench) for
[FreeCAD](https://www.freecadweb.org). This month we are all very happy
because finally we were able to finish the release of [version
0.18](https://github.com/FreeCAD/FreeCAD/releases/tag/0.18.1) of
FreeCAD. There are installers for all operating systems, Windows, Linux
and Mac. If you are still using 0.17, go get yours!
This time there are no backwards compatibility issues between 0.17 and
0.18, as there were between 0.16 and 0.17. Any file saved in 0.18 should
still open fine in 0.17, provided, of course, you didn't add 0.18-only
features such as sketcher splines. Even so, the file should yield errors
but still open in 0.17.
Check the [release
notes](https://www.freecadweb.org/wiki/Release_notes_0.18) for the
complete list of new features, and [this
video](https://www.youtube.com/watch?v=85HlYXnaxbw) made by Sliptonic
that showcases the most important new features in 0.18.
Also, FreeCAD now has a brand-new [code of
conduct](https://github.com/FreeCAD/FreeCAD/blob/master/CODE_OF_CONDUCT.md).
This might seem superfluous at first sight, because until now there
hasn't been any very serious situation in the project, but many of us
would like the FreeCAD community to be more inclusive, and this is an
important step in that direction.
As always, thanks so much to all of you who help the project in one form
or another, being by sponsoring me on
[Patreon](https://www.patreon.com/yorikvanhavre),
[Liberapay](https://liberapay.com/yorik) or
[Paypal](mailto:yorik@uncreated.net), or helping the FreeCAD project
directly by participating in coding, writing, translating, helping other
users or donating on the project's
[bountysource](https://www.bountysource.com/teams/freecad) account.
Every effort helps bringing it a step further!
I've been pretty
[busy](https://github.com/FreeCAD/FreeCAD/commits?author=yorikvanhavre)
this month fixing a lot of bugs both in 0.18 and master (most important
ones get backported to 0.18, we already issued a 0.18.1 one, and there
will likely be another one soon), but fortunately there was still time
for a series of cool improvements.
So here are the more BIM-oriented happenings of this month. Most of
these new changes are now happening in the FreeCAD master branch, which
will become 0.19 at some point (there are [pre-release
packages](https://github.com/FreeCAD/FreeCAD/releases/tag/0.19_pre)
available already!) Enjoy!
### The videos
I added two new chapters to the [Barcelona
pavillion](https://www.youtube.com/playlist?list=PLmKdGVtV5VnuE5U75CEORkjlVK_nzQQUh)
video series: One that shows how to export a model to the [IFC file
format](https://en.wikipedia.org/wiki/Industry_Foundation_Classes) for
opening in other BIM applications, and another that shows a first method
to produce 2D views from a model (other methods will follow):
### Shape2DViews can now fuse walls and structures
I will add that functionality to TechDraw Arch views too later on, since
this seems to work well now and might be a really good way to solve the
famous problem of wall joining.
Basically, the idea is that you wouldn't need to join walls anymore.
They would be all joined automatically afterwards, when you produce 2D
views. If you set the "Join Arch" property of [Draft
Shape2DViews](https://www.freecadweb.org/wiki/Draft_Shape2DView) to
True, walls and structures (so far only these two types) will be unioned
by material before creating the view, giving quite nice results:
The walls and structure objects themselves are not modified, only the
views you produce from them.
I think this might be a very good way to proceed further, as it is
really very convenient and flexible to keep different wall segments as
separate objects.
### IFC type property
The transition to our new vision of IFC support in FreeCAD is well under
way. Part of this is the ability for any Arch/BIM object to be of any
IFC type, regardless of the method used to construct it. So you can use
the wall tool to build a beam, and vice-versa. For any object in your
model, you just say what it is, a wall, a column, or simply leave it
undefined. It will be exported to IFC as you decided.
The old Ifc Role property will automatically be converted to the new IFC
Type property when opening a 0.18 file in 0.19, and version 0.18 also
has a hook to automatically convert back to Ifc Role when needed, so
this is fully backwards-compatible.
### Compound, multiple colors and transparency support in IFC
The IFC exporter has been extended to support several useful things:
- Transparency: Objects are now exported with their transparency value
as set in FreeCAD.
- Multicolor objects: Objects that have multiple colors and
transparency levels, such as windows, are now correctly exported as
such.
- Compounds: [Part
Compounds](https://www.freecadweb.org/wiki/Part_MakeCompound) are
now supported by the exporter, these objects are now exported as
multiple-solids
[IfcBuildingElementProxies](http://www.buildingsmart-tech.org/ifc/IFC4/final/html/schema/ifcsharedbldgelements/lexical/ifcbuildingelementproxy.htm).
The individual colors and transparencies inside the Compound are
exported too.
### Multiple IFC properties with same name
So far, FreeCAD didn't handle different property sets that contained a
property with a same name (for example, some custom property sets added
by Revit all contain a property named "Name"). This is now solved. As
long as they live in a different set, you can have different properties
with a same name.
### More work on dynamic IFC Attributes
Part of our new IFC infrastructure is a feature coded by Dion Moult,
that when you change the IFC type of an Arch/BIM objects, several new
properties required by that type get automatically added to the object.
These properties don't influence the geometry of the object (otherwise
if you change the type the geometry could change, which we absolutely
don't want). However, we sometimes want them to be tied to the object
geometry. For example, we want the "Overall Height" of a window to be
the actual height of the window.
So, whenever possible, these dynamic properties get automatically linked
to the actual geometry of the object. For example, The "Elevation"
property of a Building Storey gets automatically taken from its Z
coordinate, or the "Overall Height" of a window to its "Height"
property.
This gives us quite an interesting level of translation between FreeCAD
objects and IFC objects, that is fully transparent to the user.
On any Arch/BIM object in FreeCAD, look for its "IFC Attributes"
properties group. That's where they live. Try changing the IFC type,
you'll see the contents of that group adapting.
There is still more to be done there to increase that automatic
behaviour, but I am quite happy with this feature already, now really
any aspect of how a FreeCAD object is exported to IFC is available to
the user: type, name and description, attributes (the "built-in"
properties of an IFC object), properties (the "custom" properties of
an IFC object) and quantities are all settable and controllable.
### Draft objects with Area property
All [Draft](https://www.freecadweb.org/wiki/Draft_Workbench) objects
that can form a face (rectangles, wires, circles,polygons...) now have
an Area property that is set automatically when the object has a face.
So it is pretty convenient to use these objects to calculate areas.
### Ability to reorder BuildingParts children
[Building Parts](https://www.freecadweb.org/wiki/Arch_BuildingPart)
objects, which are also used underneath buildings and levels/building
storeys/floors, whichever name you like most, now have a right-click
option to reorder their contents alphabetically. Inside the FreeCAD
tree, everything is always listed chronologically. This is something
very delicate to change, although in large models it becomes
increasingly useful. This feature is mostly a test to see how it behaves
(quite well, I think) before trying to add that in other areas as well.
### Cloning entire levels
When working with high-rise buildings, we often have a same floor/storey
being repeated several times. BuildingParts now have a right-click
option to clone them up. To use that option, your building part must
have its Height property defined, so the new floor will be place at that
height above the one you are cloning.
The new floor is an independent copy, but all objects inside are clones
of the same objects in the original floor. This is not yet what we would
like I think, it would be best to have the new floor as a kind of big
all-in-one clone, but I wanted something which would export correctly to
IFC first. This system does.
Also, once a floor is cloned that way, it is pretty easy to move,
delete, etc... so at the moment it works well.
In a next move, I'm planning to add a possibility for BuildingParts to
be clones of other BuildingParts, and automatically do the management of
all cloned objects inside, in order to stay compatible with IFC.
### Space plans in TechDraw
When creating [TechDraw
views](https://www.freecadweb.org/wiki/TechDraw_NewArch) of Section
Planes, until now [spaces](https://www.freecadweb.org/wiki/Arch_Space)
were displayed as only their text tag. But in BIM work spaces are
usually very useful in early stages of a project, when you need to
arrange different areas or rooms that compose the project.
TechDraw Arch views now have a new "Fill Spaces" property that, when
turned on, will show a filled area behind the text, of the color of the
space in the 3D view, which enable you to quickly create nice
organisational diagrams.
### Section view clipping
[Section Planes](https://www.freecadweb.org/wiki/Arch_SectionPlane) now
have a "Clip view" properry, that, when set to True, will clip the
results to the dimensions of the section plane. This work with both
[TechDraw Arch views](https://www.freecadweb.org/wiki/TechDraw_NewArch)
and [Draft Shape 2D
views](https://www.freecadweb.org/wiki/Draft_Shape2DView).
### Rebars without host
[Reinforcement
bars](https://www.freecadweb.org/wiki/Arch_CompRebarStraight) so far
could only be created inside a structure object. This is no longer the
case, you can now create independent rebars outside of any host object.
To host a Rebar inside an object, you just need to set its "Host"
property. But you can now leave that property empty, just as it works
with windows.
That's it for this month I guess, thanks for reading and thanks for the
support!
Cheers
Yorik