Phases and design options

Two features that model what if and when. Both cause elements to vanish with no error message, which is why they're on the disappearance checklist.

Phases: modelling time

Every element has two phase properties:

• Phase Created — when it comes into existence
• Phase Demolished — when it stops (default None)

Every view has two:

• Phase — the point in time the view represents
• Phase Filter — how elements from other phases are drawn

Phases are defined in Manage → Phases, and they're ordered. Typical set: Existing → New Construction.

Phase filters

A phase filter maps each of four states to a display rule:

Each state gets By Category, Overridden, or Not Displayed. The graphics for Overridden come from Manage → Phases → Graphic Overrides.

That Not Displayed option is the silent killer. A view using the Show New filter does not display existing elements at all — no warning, no greying, they're just gone.

The demolition workflow

Modify → Demolish (the hammer) sets Phase Demolished to the view's current phase. This is the correct way to demolish — it preserves the element for the "existing" drawings while removing it from the "new" ones. Deleting the element removes it from every phase, including the ones where it should still exist.

Rules that catch people

• New elements take the view's phase. Model in a view set to Existing and your new walls are existing. Check the view's phase before you model.
• Rooms are phase-specific. A room in Existing and a room in New Construction are different elements even in the same space. Room schedules need a phase filter or you'll see both.
• Copy/paste carries the source phase, which is usually not what you want when pasting between phases.
• Schedules have a Phase property. A schedule set to the wrong phase quietly reports the wrong quantities.
• Linked models have their own phases, and you map them in the link's Type Properties → Phase Mapping.

Symptom → cause

Design options: modelling alternatives

Design options let you model competing versions of part of the building in one file — two lobby layouts, three roof forms — and show each in its own views.

The structure

Main Model                    ← everything not in an option
  Option Set: "Lobby"
    Option 1: "Open plan"     ← primary
    Option 2: "Enclosed"
  Option Set: "Roof"
    Option 1: "Flat"          ← primary
    Option 2: "Pitched"

• An option set is one decision. Each set has exactly one primary option.
• Options within a set are mutually exclusive.
• Different sets are independent — you can combine Lobby Option 2 with Roof Option 1.
• Views without an explicit option show the primary of every set.

Manage all of this in Manage → Design Options.

Working in an option

Set the active option in the status bar (bottom-right) or the Design Options dialog. Then:

• New elements go into the active option.
• Elements in an option are only visible and editable in views showing that option.
• To move existing main-model elements into an option: select them, then Design Options → Add to Set.
• You cannot edit main-model elements while an option is active, and you cannot edit option elements from the main model. This produces the memorable "why can't I select this?" moment. Check the status bar for the active option.

View properties

Each view has a Design Options section in its Properties (or via VV → Design Options tab) letting you pick which option from each set it shows. This is how you produce a drawing of Option 2 while the main set shows Option 1.

Accept and clean up

When the decision is made: Manage → Design Options → Accept Primary. This merges the primary option into the main model and deletes the whole option set and its other options.

Do this promptly. Design options left in a model long-term cause:

• Elements that can't be edited for non-obvious reasons
• Schedules that count option elements unexpectedly (schedules have a design-option property too)
• Confusing coordination — a link's options are resolved to primary, so your consultants see something different from what you're drawing
• Rooms and areas behaving oddly across option boundaries

Limits worth knowing

• Datums (levels and grids) cannot go in a design option. They're always main model.
• Rooms in options work but are fiddly; room boundaries crossing the option boundary are a common source of unenclosed-room warnings.
• Phases and design options interact. An element has both a phase and an option. Combining renovation phasing with design options on the same area is possible and genuinely hard to reason about — avoid it if you can.

The practical advice

Both features are correct solutions to real problems, and both are commonly used when something simpler would do:

• For two or three quick massing studies, separate files or a duplicated model are simpler than design options.
• For a renovation project, phases are unavoidable and worth learning properly.
• For a genuine client decision with drawings to produce for each alternative, design options are the right tool.

If you inherit a model that behaves strangely, check both before anything else. The active option indicator and the view's phase are the two least-looked-at settings in Revit.