Compress Settings: Display Accelerators ON or OFF?

Question

"Building Dataset Elements and Building Display Accelerators are cached by AECOSim Building Designer to speed up operation of any files containing Dynamic Views." Excerpt from Wiki entry . 
 Q1: Is it worth purging the BDA's if you are not using DV's? .We have to use DEM. The problem is that the files are stored offsite (Yes, we have PW and cahcning servers). 
 Q2: Are the Display Accelerators the same as what TFHRYDRATE.EXE used to do? If so, this would predate DV's

T_Wollet · Accepted Answer

Dominic, 
 Q1: The building display accelerators are used to cache the building resymbolization for any promoted view, not just Dynamic Views. This means that if you apply any of the fitted clip volumes using a seed view that is promoted (to a building view) you would get the performance benefit of form unification, geometry maps, plan symbols, etc. If you are never using promoted views while modeling, then you could compress the Building Display Accelerators to reduce file sizes of your working models, but this will likely not improve performance (other than PW Delta File Transfer) if that is what you are seeking. Likewise Compressing BDA's also should not reduce the file size of the DEM output. 
 Q2: Yes, same as TFHydrate. 
 -Travis

Steve Cocchi · Answer

Just to add... Building Dataset Elements are part of the process that automatically scans each DGN file when opened to insure that the levels used by your Family+Part system are available for DVs. If you are not using DVs in any fashion whatsoever, then you probably won't need this. And in that case you can set BB_DVDATASETELEMENTS = 0 to prevent those levels being written to each DGN. Should you ever venture into DV-land, however, you will definitely need to reset it to =1 in order for Part resymbolization to work. More information is available in the Help under "Configuration Notes" and in our Wikis - communities.bentley.com/.../compress-options-can-affect-drawing-view-performance.aspx 
 communities.bentley.com/.../8252.aspx 
 As Travis mentioned, Display Accelerators is what we formerly referred to as TFHydrate, originally introduced in Bentley Architecture V8i, and helps to increase DV performance at the expense of a slight increase in file size. It's essentially generating Parasolid bodies within each Building element which translates to faster processing vs. the older "recipe" method. The second post by Pradnya in this older thread explains it well: 
 communities.bentley.com/.../158639.aspx