Questions, grouped by workflow.
Jump directly to the comparison tool, saved model history or collaborative reviews.
Comparison Tool
Files, privacy, display modes and advanced comparison controls.
Which file formats do we support?
The tool supports binary and ASCII STL, Wavefront OBJ and 3MF. The two sides can use different formats. 3MF units and build transforms are resolved before comparison, while STL and OBJ source coordinates are preserved because those formats do not reliably declare units or an up axis.
Do my files leave the browser?
A normal comparison runs locally in your browser and the selected models are not uploaded. A file is sent to the service only when you deliberately use a cloud feature, such as adding a revision to a Project or sharing a review link.
What does the volumetric diff show?
The tool aligns the models, converts their occupied volume into a comparison grid and separates geometry into added, removed and unchanged regions. This makes the result useful even when the source meshes have different triangulation.
What are the advanced display and alignment options?
You can switch among Voxel, Git, Heatmap and Overlay views, adjust comparison resolution and sensitivity, choose automatic, floor, center or no alignment, and change between Classic, Colorblind and Contrast palettes. Tooltips beside the controls explain the effect of each setting while you work.
Why does adding a third model require an account?
A signed-in comparison can keep three loaded models, switch among all three pairs and create a circular pair animation. The standard two-model diff remains available without an account.
How large can a model file be?
The browser comparison accepts files up to 80 MB each. Actual processing speed depends on model complexity, selected resolution, available memory and the device running the browser.
Projects and Revisions
Saved model history, account access and plan limits.
What is a Project?
A Project is the long-lived home for one part or design. It groups model revisions and lets you reopen the history instead of rebuilding context from separate files each time.
What is a Revision?
A Revision is a saved model state inside a Project. Revisions can be compared with other states in the same history, so you can inspect what changed between design iterations.
Why do Projects require an account?
Projects persist files and history between browser sessions. An account is needed to associate that private cloud data with its owner and to enforce storage and revision limits.
What does a free account include?
A free account includes 1 Project, up to 20 revisions in that Project and 500 MB of cloud model storage. It also unlocks the third-model comparison flow.
What does Premium add?
Premium raises the account to 10 Projects, 100 revisions per Project and 2 GB of cloud model storage. It also raises review-link limits and allows review links to be extended.
Reviews and Approvals
Public review links, rounds, expiration and reviewer access.
Does a reviewer need an account?
No. A recipient can open the review link and inspect the interactive 3D comparison without signing in or installing CAD software.
Can I share a comparison made in the Free Diff Tool?
Yes. After a successful comparison, use Share for review to create a link. This is an explicit cloud action, so the models needed for that review are uploaded when you confirm it.
How many review rounds fit in one link?
One review link supports up to 20 rounds. A new round keeps the discussion and the changing model states together under the same review.
How long do review links remain active?
Free review links last 7 days. Premium review links last 30 days and can be extended. Revoking a link closes access immediately.
How many active review links can an account keep?
A free account can keep 1 active link and create 3 new links per 30 days. Premium allows 10 active links and 50 new links in the same window.