ArcSDE CAD Client #2

What It Is and Isn’t

I had the flu yesterday and now I’m feeling better. With a toddler in the house it was good to get back to work so I could get some rest! I have received a good number of emails and comments about this series and I thought I should spend a moment to set some expectations.

CAD Client is one of those software products that I have always liked. It only really has 5 functions: LOGIN/LOGOUT, STORE, RETRIEVE, IDENTIFY and SETTINGS. It is NOT a GIS desktop mapping application. It doesn’t have any analysis functions. It doesn’t include any editing functions (other than the CAD applications). It doesn’t perform any thematic mapping. What it does do however is allow you to STORE CAD entities in ArcSDE and to RETRIEVE CAD entities back into CAD. It will create CAD entities out of GIS features RETRIEVEd from ArcSDE and will create GIS features out of CAD entities STOREd into ArcSDE. It gives you the ability to IDENTIFY and edit the tabular attributes of the GIS features you have RETRIEVED from ArcSDE. It has CAD conversion built into the STORE and RETRIEVE operations.



CAD Client is based ArcSDE 3.x technology, before the invent of the ArcGIS geodatabase format, upon which ArcSDE version 8.x and the current ArcSDE 9.x use with ArcGIS desktop and Server applications. ArcSDE CAD Client is a full read/write client of ArcSDE simple features. ArcSDE geodatabases use simple features to store geometry but have a system of other tables and functionality bundled together that add intelligence, and behaviors to the data stored. ArcSDE CAD Client was not built to understand the geodatabase and is therefore a read/only client of the ArcSDE geodatabase.

There are two "CAD Client" applications from Bentley Systems, the makers of Microstation that provide support for the modern geodatabase and use the disconnected editing technology of ESRI's ArcObjects to make editing transactions against an ArcSDE geodatabase (I'll dedicate another post for these). Autodesk also has a connection to ArcSDE data, but like the ArcSDE CAD Client from ESRI it is based on the C-API (not ArcObjects) and old-school simple feature ArcSDE database layers.

There is a tool in ArcGIS to convert a simple feature database into a versioned, multi-user geodatabase. This would allow you to support a data building workflow where you STORE data using CAD Client and then turn it into an ArcGIS geodatabase.

CAD Client is also well suited for read/only access to the feature stored in geodatabases.

Perhaps the most limiting feature of CAD Client when working with geodatabases is that it is unable to read geodatabase style annotation. CAD Client only reads and writes ArcSDE style annotation features or Annotation stored in a Coverages served up by ArcSDE for Coverages. Another catch-22 is that ArcMap can only edit geodatabases and not simple features. You could create ArcSDE simple feature data with CAD client but to edit it in ArcMap you would have to convert it to a versioned geodatabase, in doing so you make the data read/only to CAD Client. This limits you to workflows where you edit in one or the other environment, or where you have some data publishing intermediate workflow to move data back and forth between one format or the other.

Some customers customize CAD Client using the included C-API, AutoLISP, Microstation Basic, and Automation tools to annotate and perform various forms of thematic mapping from tabular attributes. Some have even forgone the CAD Client interface altogether in favor of building their own application inside AutoCAD or Microstation using the included CAD Client API functions to access ArcSDE data directly.

Continue to Part #3