Revit 2021.1.9 collaborate pro grids randomly deleted

[laurenk]

GRIDS and other elements have gone missing/deleted from our collaborate pro model. We have 5x users working simultaneously and no-one is claiming to have deleted these elements.

Last week, a few grids went missing and we thought maybe someone had accidentally deleted them. 

We created new grids in place of the missing elements, audited, compacted the model, updated from 2021.1.7 to 2021.1.9. We were hoping that any possible corruptions would be fixed but today...

ALL GRIDS have gone missing. There are no longer any grids in our model.

Can someone please advise if there is any way to establish when the elements were deleted?

And, whether this was caused by a user or was some kind of file corruption? 

Is this a known issue for collaborate pro files? 

We cannot have elements (especially grids!) randomly deleted from our models. If grids are deleted, dimensions will drop out which will be unacceptable during procurement and construction.

I have attached a journal file from yesterday - not sure if this will help?

Appreciate your urgent response please.

[laurenk]

We have established the following:

1. Adjusting the crop boundary of a section causes automatic deletion of some grids. 

2. Synchronising to Central causes automatic deletion of some grids. 

3. Some walls, grids and other elements are rotated and the angle is not a whole 90 degrees to an adjacent element. ie. 89.9999999 degrees and/or 90.0435464 degrees. There seems to be multiple variable angles between elements.

We wonder if this could cause Revit to delete an element (grid) which is not set to a precise angle.

Please see journal file below - I hope this will reflect some of the tests we have run with adding grids, adjusting crop boundaries, sync & auto deletion of grids. 

Let me know if anyone comes up with ideas.

[laurenk · Accepted solution]

Please see solution below..Incase anyone is following this thread.

It's taken 3 days to adjust elements and views in our model. Tags and dimensions have dropped out. It will probably take another 3 days to replace all those elements which is quite frustrating. 

1. Ensure all elements are rotated precisely with no variation in angles less than 0.000001 degrees (6 decimal places).

Note- 0.0000001 degrees (7 decimal places) seems to be acceptable and using ctrl to force a line orthogonal (vertical or horizontal) often results in these variations.

2. Create new sections & elevations aligned precisely to elements.

3. Create new grids orthogonal to elements. Again ensure precision. Pin grids.

4. Delete offending sections & elevations 

The crop extent of the new sections & elevations should now be adjustable without grids automatically deleting. 

It seems (to me) to be a glitch where the grid is associated with the crop boundary. If the crop is extended vertically the grid heads adjust accordingly. Where the view is not precisely orthogonal to the grid (within 6 decimal points), revit can't compute the offset to grid head and deletes the grid without warning.

That is my theory anyway. I'd suggest ADSK review and confirm this behaviour for peace of mind.