The Part Workbench and the PartDesign Workbench use the same preferences. They can be found in the Part/Part design section of the Preferences editor. This section will only be available if one of the workbenches has been loaded in the current FreeCAD session.
There are four tabs: General, Shape view, Shape appearance and Measure.
On the General tab you can specify the following:
|Automatically check model after boolean operation||If checked, the Boundary representation (BRep) of the model is validated after boolean operations.|
|Automatically refine model after boolean operation||If checked, the model is refined after boolean operations.|
|Automatically refine model after sketch-based operation||If checked, the model is refined after changes to source sketches of objects.|
On the Shape view tab you can specify the following:
|Maximum deviation depending on the model bounding box||Maximum linear deflection of the tessellated objects from their surface.|
|Maximum angular deflection||Maximum angular deflection from one tessellated object section to the next section.|
On the Shape appearance tab you can specify the following:
|Shape color||Color for new shapes. If the option Random is set, a random color is used instead.|
|Shape transparency||Transparency for new shapes introduced in version 0.21.|
|Line color||Line color for new shapes.|
|Line width||Line thickness for new shapes.|
|Vertex color||Color for new vertices.|
|Vertex size||Size for new vertices.|
|Bounding box color||Color of bounding boxes in the 3D view.|
|Two-side rendering||If checked, the color of the interior side of faces will be the same as the exterior side. If not checked either the backlight color, if enabled, or black will be used instead.|
|Text color||Text color for document annotations. There is currently no dialog to add annotations to documents. Annotations can only be added using the Python console with this command:
This console is shown using the menu View → Panels → Python console.
On the Measure tab (introduced in version 0.21) you can specify the following:
|3D color||Color for 3D linear dimensions.|
|Delta color||Color for delta dimensions (parallel to the global X, Y and Z axes).|
|Angular color||Color for angular dimensions.|
|Font size||Font size in pixels.|
|Bold||If checked, font style bold is used.|
|Italic||If checked, font style italic is used.|
|Font name||The font to use.|
|Press this button to update existing measurements.|
In order to display an object efficiently its surface is tessellated, i.e. it is displayed with some small deviations from it real surface. This applies not only to PartDesign models, but also to other objects in FreeCAD.
There is a lower limit for the tessellation of 0.01%. If you really want to spend the additional time you can reduce the lower limit even further by opening the menu Tools → Edit parameters... This opens the parameter editor where you navigate to BaseApp → Preferences → Mod → Part.
Right click on Mesh deviation choose in the context menu Change value. Set the value to the minimum tessellation of your choice. Please keep in mind that the value is in %, i.e. for a value of 0.005% you have to enter "0.00005". The smallest value possible is 1e-7. Note: In the preferences menu you will still see 0.01% even if you set a lower value.