For now I will eliminate the beveling of bolt heads and nuts, the added number of polygons is too hard to justify and the bevel doesn't really add much when your zoomed out at building scale anyways (in other words you really can't see the bevel).
There is always an option to turn the anchor bolts on or off, that is a given. Some users may want this function others may have absolutely no use for it. It will be there if you need and want it.
For now I am going to go with 1/2" and 5/8" anchor bolts, I can always add more sizes later by request. The standard sizes of anchor bolts are per a specification I pulled from Fastenal (major manufacturer of fasteners in the US). I will start with 10", 12" and 14" lengths.
For the square washers I will give an option between 2"x2" and 3"x3", with the 3x3 being the more typical I would think with the latest 2012 and 2015 cycle of ICC codes. The exact dimensions of the square washers are per Simpson Strong-Tie's offering in there wood fastener manual.
The hex nuts are per the Machinery Handbook 27th Edition.
If anyone has a metric spec. for anchor bolts (L-bolts) please send it my way and I can add in the metric equivalents.
I think the intent with providing the anchor bolts is partly a graphical representation and also for estimating. Ultimately the exact layout of the sill plates will drive the number and location of the anchor bolts as well as any requirements from an engineer for tightening up the spacing due to lateral loads and shearwalls.
Per the code (IRC/IBC) you are required to have at least two (2) anchor bolts per sill plate segment and the bolts must be within 12" of the end of the segment and no closer than 7 bolt diameters (3.5" for a 1/2" DIA bolt). Max. spacing is 6' o/c with 7" min. embedded.
So even if I lay out my bolts starting 12" from the edge of the foundation and space them at 6' o/c there will probably still be some additional bolts required since there will be sill plate splices (for buildings larger than 16'x16').
I've always wondered if the builders actually give this much thought as they are placing their anchor bolts.
Another question I have is one would not want the anchor bolts to clash with the Floor Joists or Trusses. Do the contractors typically layout the location of the anchor bolts to ensure that this does not happen.
Your right there are a lot of constraints on the location of the anchor bolts, hence it actually might be useful to a designer to have them in the model to see potential issues as those raised above.