CUTL opens full 3D STEP models straight in the browser, so you and your customer or supplier can look at the same part without anyone installing CAD. Rotate it, measure it, cut a section through it, pin a comment on the exact face that worries you, and agree on the part before anything is cut.
From the same model you can produce a PDF drawing set and, for assemblies, a quotation. Nothing is drawn or entered twice.
Try it without an account
The public viewer at app.cutl.online/step-viewer lets anyone drop a .step or .stp file and look at it in 3D, with no sign-up.
| Limit | Value |
|---|---|
| File size | Up to 40 MB |
| Uploads | 5 per hour and 20 per day from one address |
| How long it lasts | The view is temporary: close the tab and it is gone |
If you create a free account within 2 hours of the upload, the model is kept and becomes a normal review in your account, ready to comment on and share.
Open a STEP model
In your account, STEP files (.step and .stp) are uploaded as reviews.
If an identical file is already uploaded, CUTL offers to open the existing review instead of creating a duplicate. When the design changes, use Upload new version and add a short note about what changed; older versions stay available read-only.
Viewer tools
The toolbar works the same on single parts and assemblies. Most tools have a keyboard shortcut, shown in brackets.
| Tool | What it does |
|---|---|
| Measure (M) | Distance between two edges or faces, Area of a face, Diameter of a hole, round face or circular edge, and Angle between two edges or two faces. |
| Cross-section (S) | Cut the model with a plane on the X, Y or Z axis and move the plane to look inside. |
| Explode (E) | Spread an assembly apart by a chosen percentage to see how it fits together. |
| Overall dimensions (D) | Show the overall size of the model. |
| Save image | Save the current view as a picture. |
| Millimetres or inches | Switch the units used for readings. |
| Render modes | Shaded (1), Mixed (2) or Wireframe (3). |
Work with assemblies
Multi-body STEP assemblies open with their component tree intact. You can:
| Action | What it does |
|---|---|
| Browse the tree | Walk the assembly structure component by component. |
| BOM | See the parts list with quantities, filter it by name, and export it as CSV. |
| Isolate | Show one part or sub-assembly on its own and hide everything else; Show full assembly brings the rest back. |
| Fit | Zoom straight to a selected part. |
Review together
Reviewing a part in CUTL is a shared thread on the live model, not an exported screenshot.
Discuss right on the model
Click a face or edge to start a comment anchored to it, or post a general comment about the whole model. Pins stay attached to the geometry they mark, so "this radius" or "this hole" is never ambiguous. New comments, pins and comment counts update live for everyone who has the review open. Threads can be replied to, resolved and reopened.
Invite a collaborator
Inviting is for administrators of the team that owns the review. Open the Social panel on the left edge of the viewer, click Invite collaborator (the envelope), enter the person's name and email address, and set the date their access expires. Other team members can view and comment, but do not see the invite button, the reviewers list, visibility templates or the review banner.
- An external person receives an email with a magic link. On opening it they confirm with a 6-digit code sent to the same address, so no password or CUTL account is needed.
- Someone who already has a CUTL account is added directly and opens the review from their own account.
The reviewers button next to the envelope lists everyone invited, with their email, expiry date and a badge (Full model or Parts hidden with a count). Each row has three actions: Edit visibility (the eye), Send invite again (the paper plane) and Revoke (the red cross). A revoked person can be invited again later and starts over with a fresh code.
Invited collaborators can view the model and take part in comments, but they cannot download the STEP file, create drawings or open the PMI panel.
Hide parts from an invitee
When you invite someone to an assembly, the Visibility section of the invite dialog lists the assembly tree with a Hide box per node. Anything you tick, and everything under it, is absent for that invitee: not in the tree, the 3D scene, the BOM, comments or emails. Nothing on their screen says anything is missing.
Preview shows the 3D scene as the invitee will see it. It is a 3D preview only: during the preview your own tree, parts list and comments still show the full model.
Templates belong to that review. Applying one copies its selection onto the invitee, so editing or deleting the template later does not change anyone already invited. To manage them, open the ⋯ menu on the file's title chip and choose Visibility templates…: there you can edit, rename, delete or create templates.
Material and weight
Open Properties in the viewer. With nothing selected it shows Mass of the model; with a part selected, its Mass. CUTL works the weight out from the model's volume and the density: choose a material for the whole model or for one part, or type a Density (g/cm³) yourself. Your team can change the material; invited reviewers see the weights read-only.
Create PDF drawing
The owning team can turn the model into manufacturing drawings without opening CAD. In the viewer toolbar, click Create PDF drawing. The drawing is made from the version selected at the top left, so check it before you press. The button exists only in a review in your account, not on the public viewer: save a file to your account first if you need a drawing of it.
What you get follows what you are looking at:
| Current view | Result |
|---|---|
| A single part | A one-sheet drawing of that part. |
| A sub-assembly or the whole model | One PDF booklet: an overview with balloons and a parts list, followed by a drawing of each part. |
If the chip says Could not prepare the PDF, the message tells you why:
| Message | What to do |
|---|---|
| The version is still being processed | Wait for the model to finish loading, then press again |
| There is nothing to draw here | The view holds only purchased parts. Go up a level |
| Open a version first | Pick a version in the selector at the top left |
Nothing retries in the background, so press the button again after fixing the cause.
Drawings use first-angle projection to ISO conventions, on A3 landscape sheets with the scale chosen automatically. Drawing text is in English, Dutch or Russian; other interface languages get English drawings. Creating a PDF drawing costs no coins. The layout is standard for now: you cannot choose the paper size or put your own company in the title block yet.
PMI
The PMI panel in the viewer's left strip lists the tolerances, GD&T frames, finishes and notes the STEP file already carries, and lets the owning team add or correct requirements on the exact faces they apply to. Save all writes your changes into a new version of the review, leaving the old one as it was. See PMI for the full workflow.
Documents
The Documents tab writes assembly manuals, part and product passports and parts lists from the model, with tables and pictures that stay tied to it. See STEP documents.
From review to quote
Once an assembly is agreed, you can price it in the same place: the review has a Quotation tab that breaks the assembly into parts to make, purchased items and assembly operations. See Assembly quoting for the full workflow.
For single parts, STEP tubes and profiles are costed per metre in projects, as described in Preparing files and Quoting and cost.
Do
- Invite the customer or supplier to the review so they see the live model, measure it themselves and pin comments on the exact geometry.
Avoid
- Exporting a screenshot and emailing it for sign-off: you lose the 3D geometry, the measurements and the anchored comments, and nobody can check a size you did not think to show.
Next, see Assembly quoting to price a reviewed assembly, or Preparing files for how single STEP parts are costed.