When closing a drawing in 3D, and later re-opening and returning to 2D, some of the drawing symbols show up looking like outlines (Hangers, Sprinklers, etc)

When raising to 3D, you get the following error;

Error inserting to block table HEAD#/HH## to head dictionary

Sprinkler heads not defined in the drawing or no 3D block assigned for a sprinkler head. Going to Navis only - corrupt Persistent Model drawing? eKeyNotFound Dialog box HydraCAD

When raising to 3D, AutoCAD crashes with no error, no warning, it just closes.

You can test this by closing all open drawings then starting a new drawing using the Hydratec template, "Hydracad Imperial Default".

Draw one pipe 10' long (LN command). 

Place a length & 2" diameter on it (SZP command)

Place a 10' AFF elevation mark on it (AFF command)

Start the process of raising to 3D (S3D command).  It will then crash out without warning around step 2 (something about sprinkler heads).

When viewing your Persistent Model drawing, you see the clamshells/Pacman/bracket for the riser nipples/vertial pipes

While attempting to raise to 3D, you get this error message;

Exception Occured at AddURLToHyperlinks::HydraHeads

The drawing will still raise to 3D but you may not have sprinkler heads visible.

(TYPE_E_CANTLOADLIBRARY)

679327F1-F31E-488D-8FBC-124C4F6F588E

DAO32ServerLib.DaoComObj

When attempting to create a 3D model, you get the error; Please switch to System Model to Annotate Drops and Sprigs plus

System.NullReferenceException: Object reference not set to an instance of an object

at HCADexports.RevitConversion.create_hydrapipes_from_db()

at HCADexports.RevitConversion.create_hydrafittings_from_db(List'1 pipes, List'1 heads)

While raising to 3D, AutoCAD just crashes.  No error, no warning. 

In the status bar, it was working on Computer Generated riser nipples

When making a 3D model, the sprinkler heads appear on the floor.