4D that never leaves your laptop.
Open the IFC beside the schedule you already have. Link it once, play the build, and keep the links through every update. The model is read in your browser and never uploaded.
IFC 2x3 · IFC 4 · IFC 4.3 · .ifczip — beside a P6 XER, P6 XML or MS Project XMLWhat it is for
Links that survive the update
Links are held by Activity ID and by each element's GlobalId, not by row numbers, so next month's XER keeps them. When an Activity ID changes or an activity is deleted, or the model is re-issued, a report says what broke and suggests the fix.
Linked in minutes, not days
Each take-off line is offered an activity, with how sure the match is and why. Take the sure ones in one step, review the rest from the keyboard, and let the rules your corrections imply do the next model for you.
Never uploaded
The IFC is read by your browser on your machine and cached on the same machine. Clash checks, BCF files and video are made there too. There is no server holding your model, so there is none to approve.
Links in minutes
The model is split into take-off lines: a storey or area by element class. Each take-off line is offered an activity, judged from the storey and the trade words in your activity names and WBS, and marked High, Medium or Low with the reasons. Accept all high-confidence takes the sure ones at once; Next to review walks you through the others.
Correct a few lines the same way and the Studio proposes the rule that would have made them, such as every column to A1030. One click on Add rule, and a re-issued model links itself on open. You can also click elements in 3D, shift-click to add or remove, or use Box select, then Link to activity, or Create activity… to make the activity from the selection as one undo step.
After an update, Check links lists activities that have gone, elements that are new and elements that left, with Apply suggestions and an undo. Write to XER fields puts the count and the rule on each activity, so the P6 file of record carries the summary. In a live session, link edits reach everyone in it.
Level 1 · slabA1020 Pour slab L1High
storey Level 1 · trade: slab
Level 2 · wallA1140 Blockwork L2High
Level 2 · columnA1030 Columns L2Medium
storey Level 2 · close second
Roof · memberA1310 Roof steelLow
Accept all high-confidence (14) · 4 left to review
rule offeredcolumn → A1030
you linked 4 column lines to A1030
The critical path, in the building
Select an element and choose Show driving path: the chain of activities that drives its activity lights up across the model, and everything else turns to a ghost. Step along path moves the date to each activity in turn and selects its elements, so you can walk a client through why the roof waits on the core.
Colour by › Total float paints the whole model in four bands, from no float to more than 20 days, with finished work in grey. Hover any element for its activity, dates, float and the activity driving it.
colour by › total float
0 days or less
up to 5 days
up to 20 days
more than 20 days
finished
Edit the schedule from the model, and see the effect first
Select the work and say what should happen. Build after… adds the logic link: with two or more activities selected, the first-selected becomes a predecessor of the others; with one, you type the Activity ID it should build after. Move to week… asks for the week starting date and sequences the selection after the last unfinished activity that finishes before it (work on the selection’s storey first), and offers a Start On or After constraint, Use a constraint instead, as the second choice. Sequence bottom-up… chains one class of work storey by storey.
Nothing changes until you have seen what it does. Each edit is run on a copy first: the new project finish, the DCMA score before and after, and the checks that fail after it, with any new failure marked. A change that would make a loop cannot be applied. Apply makes it one undo step, through the same edits the grid uses, so the XER stays byte-identical except for what you changed.
adds1 finish-to-start link, A1020 → A1030
Finish2 Jun → 5 Jun · 3 working days later
DCMA score92% → 92%
Failing checksnone
Apply · one undo step · Cancel
Risk and crews, on the model
After a risk run, Colour by offers Build at P50 and Build at P80: the building as it stands on the slider date with every activity at its own P50 or P80 dates. Chance finished by this date colours each part by how likely it is to be done by then.
Colour by › Crew on site (avg heads/day) colours each zone by its average heads a day over the Monday-to-Sunday week holding the slider date, against the busiest day on the whole schedule. It is offered once a labour resource is assigned to an activity. Where two or more trades from different activities work in one zone on the same day, the zone is listed under stacked trades, week commencing that Monday; click it to select the zone and frame it.
Level 3 slab96%
Level 4 core58%
Level 4 slab21%
stacked trades · week commencing Mon 09 Mar
Level 23 trades (Drylining, M&E, Joinery) · 3 days · worst on Tue 10 Mar
Level 32 trades (M&E, Fire stopping) · 1 day · worst on Thu 12 Mar
Clashes, including the ones a schedule makes
Find clashes checks the model on your machine: hard clashes triangle by triangle, including tilted and sloping elements, duplicates among them, and clearance within a distance you set in millimetres. With Only when the work overlaps in time ticked (the default), a duct through a beam matters only while both trades are there. Under a Show filter the check covers what is shown and keeps the clashes found elsewhere.
Sequence clashes are the ones only a schedule can make: work built before what holds it up, such as a slab programmed ahead of its columns. Each comes with Fix with a link, previewed like any other edit. Workspace clashes are the stacked trades of the crew view, found week by week when labour is assigned. The Show button on a clash row frames it on the model, and Colour by › Clashes paints the open ones. Each clash has a status, Open, Accepted or Fixed, saved with the schedule. Export CSV lists them all; Export BCF writes a BCF 2.1 file for other BIM tools, with a topic for each clash between two elements. Workspace clashes are in the CSV only.
sequenceSlab L3 on Columns L3
slab A1120 starts 9 Mar · columns A1130 finish 21 Mar
Fix with a link · A1130 → A1120 FS
hardDuct D-114 · Beam B2/7 · on site together 9 – 21 Mar
clearance 50 mmPipe P-31 · Wall W-12
Export CSV · Export BCF · office-block-clashes.bcfzip
What is forecast, and what the baseline said
A mark on the date slider shows the data date; click it to jump there. Past it the date reads “forecast”, and work shown as done only because of forecast dates gets a lighter tint, so nobody mistakes a plan for progress.
Once a baseline is set, Compare with baseline splits the view: the current schedule on the left, the active baseline on the right, one camera and one slider for both. Against the baseline colours work the baseline said would be finished but is not, so a slip shows on the model as it does on the chart. Show narrows the view to the selected activities, a WBS branch, a storey, a system or a week, and This week takes the Monday-to-Sunday week holding the slider date.
Export PNG, Record video and Weekly frames take it to the meeting. The video plays the whole run at full resolution. Weekly frames saves a PNG for each Monday of the run, with the first and last day, in a zip. Both have the date burned in on an opaque background, and show both halves when Compare with baseline is on.
reads14 Mar · forecast
tintlighter where done is forecast, not reported
compareNow │ Baseline: BL-Jan
behindLevel 3 slab · baseline finish 28 Feb
Fast on big models, without losing quality
The model is drawn in a few large chunks, coloured per element, and recoloured in place: a link edit or a move of the slider never rebuilds the geometry. Geometry is never simplified and antialiasing stays on. While the camera moves, the resolution may drop for a moment; it comes back in full within 150 ms of stopping.
Measured on 4 Oct 2026 on synthetic models of 50,000 to 90,000 elements and about a million triangles; the slider, pick and playback figures come from opt-in tests we re-run before a release.
| Action | Measured | Budget |
|---|---|---|
| One move of the date slider | 3.1 ms | 8 ms |
| Playing the run, about 1.07 million triangles | 3–7 ms a frame (2.5 ms median per chunk) | 8 ms |
| Main-thread tasks over 50 ms during playback | none | none |
| Picking an element under the pointer | 0.02 ms | 2 ms |
Your model never leaves your machine
Defence, nuclear, government and data-centre work often cannot put a model in someone else's cloud. Here the model has nowhere to go. The page and its 3D code come from aimavera.com; your model never travels the other way.
-
The IFC file
On your disk, or a drive you already use.
office-block.ifc -
Your browser
Reads it in background workers, draws it, links it, checks clashes, and writes BCF, video and frames that are saved to your device.
read · link · clash · export -
This device's storage
The geometry cache, so the model reopens without being read again. The links are saved with the schedule.
geometry cache · this browser
No server
No upload and no AI provider. The model is never sent anywhere; in a live session the schedule and the 4D links travel between browsers; the model and the clash list do not.
What it reads
- Models: IFC 2x3, IFC 4 and IFC 4.3, and .ifczip. More than one at once: the services beside the structure, each with its own tick to show or hide.
- Schedules: Primavera P6 XER and P6 XML, and Microsoft Project XML, or one built in the Studio.
- Out: IFC 4.3 with the 4D links, as an IfcWorkSchedule naming each element by its GlobalId; BCF 2.1; CSV; PNG, video and weekly frames. The XER stays the file of record.
Honest limits
- No photoreal rendering. The view is for sequence, not for a marketing film.
- Very large federations: simplify first. We have measured a 90,000-element, million-triangle model on an Apple M2. Larger files depend on the machine’s memory, and a multi-GB federation is still workstation work; split it by discipline or storey and open the parts you are sequencing.
- Live sharing of links has a size limit. The links can hold over 200,000 element links with ordinary Activity IDs; past that the Studio tells you and each planner keeps their own. Rules and line links cost far less, so lean on them.
- Clearance is measured box to box. Hard clashes are checked on the real triangles; clearance uses each element’s bounding box, so it can over-flag angled or curved work, and it misses close calls between elements whose boxes already overlap.
- BCF opened by other tools is the real test. The files were validated against the official BCF 2.1 schemas; we have not yet checked each BIM tool’s import, so how a tool reads them is up to that tool.
- Video needs the tab in front. Record video uses the browser’s own recorder, so it is offered only where the browser can record a canvas, and it stops, keeping what it has, if you switch tab. Weekly frames carries on in the background. The file is WebM, or MP4 where that is all the browser records.
- Risk colours need a current risk run. The run is not saved with the file, so run it again after reopening, and after an edit the status line says the run is older than the last edit.
Open the model beside the schedule.
Free to open, no account, nothing uploaded.