Revit Add-ons: Karo.WhatsChanged: A Local Change-Audit and Investigation Layer

Overview

Karo.WhatsChanged is a model-coordination add-in for Autodesk Revit that records a reference state and identifies what changed after linked consultant models are reloaded. It is designed to replace broad visual comparison with an element-level audit that surfaces additions, deletions, moved geometry, coordinate changes, and parameter modifications. The add-in keeps comparison data locally in SQLite rather than uploading project geometry to a cloud service. Its principal audience is BIM coordinators, architects, engineers, and multidisciplinary delivery teams that need to assess the impact of updated architectural, structural, or MEP links.

Core Workflow

Establish a baseline. The add-in records a personal reference state for the host model and its links on the user’s workstation.
Reload updated links. When a consultant model is refreshed, WhatsChanged compares the new state with the stored baseline.
Review detected changes. An audit grid groups and counts Added, Modified, and Deleted elements and supports filtering by change status, category, and source document.
Inspect the delta. Select an item to review before-and-after parameter values and geometry or coordinate differences.
Locate the affected area. Synchronize the selected result with the active Revit view or create a dedicated 3D view with an automatically framed section box.
Document the review. Export results to Excel or a formatted PDF for coordination meetings, issue logs, and follow-up.
Advance the reference state. After the update is reviewed and accepted, establish the appropriate new baseline for the next comparison cycle.

Changes It Detects

Added elements: New model objects introduced since the stored reference state.
Deleted elements: Objects present in the baseline but missing from the updated model.
Modified geometry: Changes to an element’s form, size, or geometric representation.
Relocation and coordinate shifts: Movement in 3D space, including changes that may affect alignment, clearances, penetrations, supports, or hosted relationships.
Parameter changes: Differences in instance and type data, with exact previous and current values for fields such as levels, offsets, dimensions, and type parameters.
Host and linked-document changes: Results can be filtered by the host document or a specific RVT link, helping isolate responsibility and scope.

Review and Navigation Tools

Interactive audit grid: Presents detected changes in a sortable, filterable list with category counts and quick status filters.
Deep parameter inspector: Shows the specific fields that changed and their before-and-after values rather than only marking an element as modified.
View synchronization: Selecting a result can zoom to and center the affected element in the active view.
Focus Dim: Keeps contextual geometry visible while visually de-emphasizing surrounding content, making the changed object easier to recognize without losing spatial context.
Automated 3D section box: Generates a dedicated 3D inspection view framed around an item that is difficult to understand in plan, section, or elevation.
Excel and PDF reports: Produces structured outputs suitable for coordination sessions and change records. The vendor describes them as meeting-ready; teams should still confirm fields and formatting against their own issue-management standards.

Data Architecture, Privacy, and Worksharing

Comparison is performed locally using SQLite. According to the vendor, project geometry and diff databases remain on the workstation or office network, with no cloud upload, cloud-processing delay, or model-size cap. This architecture may suit projects governed by nondisclosure, healthcare, enterprise, or other restrictive data policies, but organizations should independently validate storage paths, access controls, backup behavior, encryption expectations, retention, and software telemetry before approval.

The product supports Revit Server and BIM 360/Autodesk Construction Cloud models, but the baseline is described as a local, personal reference point per workstation. That is important operationally: two coordinators may compare against different baselines and therefore receive different results. Teams should define who owns the comparison cycle, when a baseline is accepted, where reports are stored, and how findings are distributed.

Value for BIM Coordination

Reduces manual comparison: Directs attention to detected deltas instead of requiring coordinators to scan entire updated models.
Improves impact assessment: Exact parameter and coordinate differences help distinguish a significant coordination change from a minor, unrelated edit.
Speeds visual investigation: Synchronized views, Focus Dim, and section boxes reduce the effort required to locate linked elements.
Supports accountability: Exported reports can provide a dated record for meetings, consultant questions, and downstream task assignment.
Works across disciplines: The same process can review architectural, structural, and MEP link updates, improving consistency in multidisciplinary coordination.
Preserves local control: On-premises comparison avoids sending full models to another cloud platform solely for change detection.

Limitations and Interpretation

Detection is not impact analysis: The tool can identify changed elements, but it cannot determine whether a change is acceptable, coordinated, constructible, or contractually significant.
Results depend on the baseline: A missing, stale, reset, or workstation-specific reference state can alter what appears in the next comparison.
Model churn can create noise: Recreated elements, family changes, altered identifiers, or broad consultant cleanup may yield many results that require triage.
Deleted items need contextual review: A deleted linked element cannot always be navigated like a current element; reports and stored prior-state data may be more important for investigation.
Coordinate changes require extra care: Shared-coordinate, link-positioning, or origin changes can produce widespread movement with major coordination implications. Teams should verify whether the shift is intentional before accepting a new baseline.
Report export is not issue management: Excel and PDF records do not by themselves assign responsibility, maintain issue status, or synchronize with a CDE issue workflow.
Performance claims are vendor statements: “In seconds,” “zero cloud lag,” and “no file size limits” should be validated with representative project models and hardware.

Recommended Implementation

Select representative host and linked models, including at least one large multidisciplinary project.
Define the authoritative comparison owner, baseline event, link-reload protocol, and report repository.
Establish triage rules for additions, deletions, movement tolerances, parameter changes, and coordinate-system changes.
Test element recreation, family/type replacement, link unloading, nested links, phase changes, and shared-coordinate updates.
Confirm that users can consistently locate active and deleted changes and that exported reports contain the data required for meetings and issue creation.
Benchmark scan time, database growth, and navigation performance on supported workstation configurations.
Complete IT review of the MSI installer, licensing traffic, local SQLite data, network storage, backups, retention, and uninstall behavior.
Document when a reviewed model becomes the new baseline so subsequent comparisons remain consistent.

Compatibility, Licensing, and Support

Supported Revit versions: Revit 2023 through 2027.
Operating system: Windows 10 or Windows 11, 64-bit.
Current vendor release: Version 1.11.9, distributed as an MSI installer at the time of review.
Trial: A 14-day full-featured evaluation.
Pricing: US$15 per month or US$120 per year, with cancellation permitted under the vendor’s stated subscription terms.
License mobility: The vendor states that a license can be transferred to another computer while preserving remaining subscription days.
Future support: The vendor says future Revit versions are included while the product is maintained. This is a forward-looking vendor commitment, not a guarantee of indefinite compatibility.

Assessment

Karo.WhatsChanged addresses a specific but costly coordination problem: understanding the consequences of a reloaded consultant model. Its strongest capabilities are element-level classification, exact parameter and coordinate deltas, rapid visual focus, automated 3D framing, and locally stored comparison data. It is best viewed as a change-audit and investigation layer rather than a replacement for clash detection, model checking, issue management, or professional coordination judgment. The local-baseline design offers privacy and speed advantages but requires disciplined ownership to keep comparisons consistent across a team. For projects with frequent link updates, a controlled trial using real consultant exchanges should reveal whether the reduction in manual review justifies the subscription and governance overhead.

Sources

Karo Modum — Karo.WhatsChanged product page. Primary source for product purpose, features, workflow, local SQLite processing, current version, compatibility, trial, pricing, license transfer, and vendor claims.
Karo — How to Track Changes in Linked Revit Models. Vendor demonstration used to corroborate audit filtering, parameter inspection, view synchronization, Focus Dim, automated section boxes, reporting, operating-system requirements, and worksharing statements.
Karo Modum — Terms of Service and EULA. Used for general commercial context, payment, subscription, licensing, support, warranty, and independent-developer caveats.