Question

Is it possible to read an AutoCAD drawing and then write to a new drawing-preserving the autocad_entity_handle from the original drawing in the new drawing?

  • 19 January 2023
  • 3 replies
  • 4 views

Badge +1

I use FME for updating several things in AutoCAD drawings (dwg) and writing out to new drawings using acad reader and writer. At present, when the new drawing is completed, the autocad_entity_handle is different on each object in the new drawing.  Is there any way to preserve the original autocad_entity_handle from the original drawing in the new drawing?

Thanks!


3 replies

Badge +20

It should be theoretically possible (expose autocad_entity_handle via AttributeExposer) but FME follows the rule that handles are unique within a drawing.

Imagine you read in 2 drawings and some features come in with the same handle. How would the writer handle that? (Pun intended 😁)

In the example below I read the same dwg file twice. Notice the duplicate handles. If FME preserves them, it would result in an invalid dwg definition.

autocad_entity_handleThis article explains the behavior of handles and names in Autocad: About Entity Handles and Their Uses (AutoLISP) | AutoCAD for Mac | Autodesk Knowledge Network

Badge +1

I understand the concept of handles and risk of duplication. If I take this into consideration when writing (such as reading and writing one drawing at a time, it should be avoided. I thought I'd tried the exposer, but when I write, the handle is still new. I'll check again.

Badge +20

I understand the concept of handles and risk of duplication. If I take this into consideration when writing (such as reading and writing one drawing at a time, it should be avoided. I thought I'd tried the exposer, but when I write, the handle is still new. I'll check again.

Maybe someone from Safe can be of more help here.

Reply