I have tried dynamic and cached both have missing elements or linework? would it have anything to do with this message?
"The model may contain elements outside of Solids Working Area! To analyze please use the 'SWA Info' tool found on the Building Designer Ribbon workflow, View>Solids Working Area>SWA Info."
we are working to real world co-ordinates? would this have anything to do with display quality?
look at: https://communities.bentley.com/other/old_site_member_blogs/peer_blogs/b/marc_thomass_blog/posts/setting-up-in-the-real-world-or-quot-where-do-we-model-quotgo to recomandation 6 : Relocation of the Global Origin
you have to define a new global origine
Hi Rik, Richard,
I will edit that portion of the blog.
Recommendation 6 is "Do not model more than 5,000,000,000 UOR away from Design File Centre."
The notes about use of GO= are additional information about practices in use at the time I originally wrote it, the blog does not make that clear. Also geo-referencing enables the same coordinate placement behaviour.
Relabelling the Global Origin (not relocation! The Global Origin never moves) does not resolve any of the potential rounding errors that may occur when complex 3D operations are carried out on elements that lie outside the SWA.
Geo-referencing is our recommended method for handling the relationships between building models and site or civils information that is at real-world coordinates. I have written a series of pieces on this and am currently revisiting them.
Regarding the original question:
Working at real world coordinates is fine for 2D and many 3D operations at the lower resolutions used by civil design. However, building models can include highly detailed elements and assemblies. For instance imagine some small bore pipework or detailed architectural elements modelled at real-world coordinates and orientation. To ensure that complex building objects are handled correctly OpenBuildings files need to have the default 1000 UOR/mm resolution (Recommendation 5 in the blog)
When creating DVs, as well as calculating the geometry at the cut-plane, OpenBuildings also calculates unification of parts (either the same parts or different parts that have a common unifier specified in their definition) and calculates resymbolisation and auto-annotates as specified where discipline rules are applied.
The floating-point arithmetic involved in calculating these has limitations "Squeezing infinitely many real numbers into a finite number of bits requires an approximate representation". Put crudely (I'm not a computer scientist) as a model moves further away from the design file centre the numbers get bigger and the rounding errors that occur in floating-point calculations can accumulate resulting in inconsistencies in calculated geometry; i.e. missing elements and visible edges.
This limitation is common to all applications (search for floating point errors in Excel!) which is why all 3D CAD applications have limited modelling spaces. MicroStation's ability to encompass huge real-world extents in 2D operations have led many 3D workflows to follow 2D/2.5D practices resulting in the problems raised here and elsewhere.
Regards
Marc