If you want test (still in very early development) the workbench, you have to compile FreeCAD yourself. You can find a short how-to below (based on Luke's tips).
First of all, you need tools and development packages listed on the FreeCAD wiki.
Then you can clone the sources from github:
git clone https://github.com/mrlukeparry/FreeCAD_sf_master.git
Next go to the downloaded directory:
Switch to the "drawing" branch:
git checkout drawing
Create a new directory for a build (not necessary but recommended):
mkdir Build && cd Build
Run cmake and enable debug build (FreeCAD may be a little slower but easier for debugging):
cmake - DCMAKE_BUILD_TYPE=Debug ../
Compile, the number should be equivalent to the number of threads in your CPU:
An finally run FreeCAD:
Open or create a solid part. Switch to the drawing workbench and create a new page.
Double click (in tree) to open the page view.
Select a solid from the tree and create a new view. Views (dimensions too) dragging using mouse is now possible - as opposition to the old drawing workbench.
Select an edge and add a new dimension. Tip: enable the Selection view in the View menu to see what is selected.
In the Data tab you can change the radius to a diameter.
Add some other dimensions: line length, distance between points (use Ctrl to select two points), radius and diameter are available.
Back to the 3D model and change something.
The drawing should change as well.
Any good ideas? Share your opinion!