34 possible reasons why you may of lost an element in a view, and how to find it.
Possible solutions for most of the reasons in red.
1. The object or category is temporarily hidden
Reset temporary hide.
2. The object or category is hidden in the view
Press reveal hidden elements (light bulb) to check.
3. The object is being obscured by another element.
Set the model to wireframe to see if this is the problem.
4. The object's category or subcategory is hidden in the view
Check the visibility graphics for category and sub categories.
5. The object is outside the view's view range
Cut a section, if the object is visible - compare the levels with view range.
6. The view's far clip depth is not sufficient to show the object
As above.
7. The object is within a Plan Region that has clip depth set too high or low.
Check to see if object is within a Plan Region. Also make sure Plan Regions have not been turned off. Reset Plan Region's cut plan height.
Make sure Plan Regions do not have multiple enclosed boundaries, and they do not have 'incursions (e.g. like a U shape)
8. The object resides on a work set that is not loaded within the project
Check the objects workset in the originating model.
9. The object resides on a work set that is not visible in the view
Check visible worksets in the visibility graphics.
10. The object resides on a work set that is not loaded in a linked file
Check the worksets in the linked model, move the object to another workset.
11. The object resides on a work set that is not visible in a linked file
Check visible worksets in the visibility graphics of the linked file.
12. The object resides within a group (detail model) and it has been excluded from the group
Find, or place, another instance of the group. Is it there?
13. The object is part of a design option that is not visible in the view
Check design options.
14. The object is part of a linked file that is not visible in the view
Check visibility of linked files, view range, etc.
15. The object has one or more of its edges overridden to display as
Check the objects projection and cut line overrides.
16. The object is a family and none of its geometry is set to be visible in the view
Check the families visibility settings in the family editor.
17. The object is a family and none of its geometry is set to be visible at the view's detail level
Check the families visibility settings in the family editor.
18. The object is set to not be visible at the category's detail level
Check the families visibility settings in the family editor.
19. The element has been placed outside the view's crop region (visible extents)
Click Do Not Crop View, and zoom extents to check the location of the object.
20. The element is an annotation object & does not reside entirely within the annotation crop region
Turn off annotation crop region to clarify.
21. The object's phase settings or the view's phase settings prevent the object from displaying in the view
Check what phase the object is in, this can be found in the objects element properties.
22. The view's discipline is prohibiting the visibility of the object
Set the view to coordination in the element properties.
23. The object is affected by a filter applied to the view
Check what filters are applied under the filters tab in the visibility graphics.
24. The object is subject to an element override, set to background color
Change the background colour (from black to white or vice verca) to clarify.
25. The object is subject to a category override, set to background color
Change the background colour (from black to white or vice verca) to clarify.
26. The object style is set to background color
Check under visibility graphics, or follow the step above.
27. The object is constrained to a scope boxes that is not visible in the view
Click reveal hidden elements (light bulb) to see if any scope boxes are hidden.
28. The extents of the object itself don't permit it to be seen
Is the object too big (zoom extents) or too small...?
29. The object is a mass, and 'Show Mass' is turned off
Turn on show mass
30. The object's host view has been deleted (area boundaries)
31. The view's scale is prohibiting the object's visibility
Check the settings for the object in element properties under 'hide at scale coarser than.'
32. The object is a linked instance with coordinates too great for Revit to handle
33. The user has incorrectly identified the link instance to which the element belongs
34. The object is in a link that is not in its correct position
Zoom extents to locate the linked model, and reset it to it's correct location.