Compare two revisions of an IFC model

Introduction

Every time a designer delivers a new version of an IFC model, the same question comes back: what changed? SeveUp App keeps each version as a revision of the same model. You can then compare two revisions right in the 3D scene, see the effect on IDS compliance, go back to an older version and download its file.

Before you start

• The model has at least two revisions. Add a new one with Upload revision, in the "Revisions" tab of the model page.
• Both revisions have finished processing. The comparison relies on signatures computed while the data is processed.

Compare two revisions in 3D

1. Open the model page and click View in 3D. The viewer opens the version displayed on the page.
2. In the toolbar, open the "Coloring" menu and choose Compare two versions.
3. The "Version comparison" panel opens. The "Compare to" field suggests the previous version by default. Pick another version from the list if needed.

The scene is colored according to the legend: "Added", "Shape or position changed", "Properties changed" and "Unchanged". The comparison goes one way: the version open in the viewer is compared with the version chosen in "Compare to". To compare two older versions with each other, first open one of them in the viewer.

In a federated 3D view, each model is compared with its own previous version. The panel says how many models are compared; click a model's name to see its details or change the version it is compared to.

Read the changed objects

The panel counts objects by state:

• "Added": present in the displayed version, absent from the other;
• "Shape or position changed": the geometry or location changed;
• "Properties changed": at least one property changed;
• "Removed": present only in the other version, marked "not in scene".

The number of unchanged objects is shown below. Click a state to list its objects, with their name and IFC class. The list loads 100 objects at a time; Show more loads the next ones. Click an object to select and frame it in the scene. A removed object does not exist in the displayed version: it is listed, but it cannot be selected.

For a changed object, the Details button shows the properties that changed, with the old value struck through and the new one. If only the shape changed, the message "No property changed (only the shape did)." is shown.

Follow the IDS compliance gap

When IDS requirements are checked against the model, the "IDS conformity" section of the panel shows how they evolve between the two versions. Each requirement that changes gets a label:

• "Regressed": the number of failures goes up;
• "Improved": it goes down;
• "New": the requirement was not evaluated on the other version;
• "Removed": it is no longer evaluated on the displayed version.

The number of failures before and after is shown on the same line. It adds up failing objects and presence failures. If an IDS file changed version between the two revisions, its requirements appear as new or removed: they are never matched by name.

Requirements that do not move are only counted. If none changes, the panel says "No requirement changes between the two versions."

Revision history and IFC download

The Revisions tab of the model page lists every revision, the most recent first, marked "Latest". For each one, the table gives:

• the "Version" (v1, v2…);
• the "File": file name and IFC schema;
• the "Source": "Manual" for a revision uploaded by hand, "Trimble" for a version received from Trimble Connect;
• the "Size", the "Received" date and the "Processing" state.

The actions on each row:

1. Show makes this revision the displayed version of the page. The "Health" and "Dashboard" tabs and the "View in 3D" button follow it. The same choice is available in the "Displayed version" selector, and Back to latest returns to the most recent one.
2. View in 3D opens this revision directly in the viewer.
3. Download gets the IFC file of this revision.
4. Jobs shows processing progress, and Retrigger restarts the conversion from the beginning.

For some large models, a "Light version" may also be offered for download. The original remains the reference.

What can go wrong

• "This model has no other version to compare." The model has a single revision. Add one with "Upload revision".
• "Comparison is not available yet": one of the two versions does not have its comparison signatures yet. They are computed on the next data processing.
• "Shapes could not be compared": only additions, removals and properties are reliable in that case.
• "A conformity run is not finished": the IDS trend is incomplete while the audit of one of the versions is running.
• "Upload revision" is greyed out: the model is synchronized with Trimble Connect. Drop the new version in Trimble, it comes down by itself.
• An older revision is gone from the list: the project's revision retention can delete the oldest ones. See Configure revision retention per project.

FAQ

Does the comparison create a new file?

No. It colors the scene and lists the differences. Both revisions stay unchanged.

Can I compare versions of different models?

No. The comparison covers two revisions of the same model. In a federated view, each model is compared with its own reference version.

Why can't I select a removed object?

It only exists in the other version, not in the displayed scene. It is listed for reference.

Is the downloaded file the one I uploaded?

Yes, "Download" gets the IFC file of the chosen revision. The "Light version", when it exists, is a separate file.