TKD

Solved: Walls converted to ifcWallStandardCase from ifcWall after exporting as IFCv4. Exported as IFCv2x3 and everything reverted back from what I can tell.

I just had the same issue where all my data tags attached to wall styles lost their association. After reading this post, I looked back at an archived version of my file and I had the same ifcWall/ifcWallStandardCase discrepancy between the two files. I recalled that I recently exported the model in my file as IFC v4. I decided to see what happened if I export as IFC v2x3. As soon as I did that, all my walls reverted back to the ifcWallStandardCase. The data tags immediately got back their association. Hope this helps.

In plan, I have used data tags that attach to my walls and automatically provide the correct assembly references for each wall style. I have had these in my working file for some time now. I've just noticed that all of my tags are no longer attached to the walls and so no assembly reference is given - just an exclamation mark symbol. Nor can I attach a new data tag to the walls. I haven't made any changes to the walls so am unsure why this has suddenly happened. Does anyone have any ideas?