Modelling in a browser
Levels, walls, doors, windows, rooms with names and areas; ducts, pipes and cable trays; plans, sections and 3D from one model. Schedules, quantities and cost lines read straight off it.
FOR LECTURERS · ARCHITECTURE, CIVIL, BUILDING SERVICES
A BIM lab that opens
in a browser.
No installation, no lab image, no IT ticket, and no licence that expires the week your students graduate. They open a link, pick a template, and they are modelling — on the machines the department already has.
Free to use · IFC 2x3 and IFC4 in and out · Runs in any modern browser
READ THIS FIRST
What this is, and what it is not
Open formats
IFC 2x3 and IFC4 import and export, BCF issue viewpoints, and IDS requirement checks. Your students' work is never locked into a format only we can read.
Not a verification tool
A model here is a design proposal. It proves nothing about structure, fire, code compliance or buildability, and it is not a substitute for the calculation and approval your course teaches.
01 / THE 60-MINUTE LAB
One session, no setup
Give students this link and nothing else: webcad-preview-app.web.app. They create a project from a template and work. Nothing is downloaded, so a locked-down lab machine is fine, and a student who is at home is on the same model as the one in the room.
- 0–5 min
Open the link. New project, choose a template, and orbit the model. Everyone is in the same place before anything is drawn.
- 5–20 min
Set the levels the brief needs, then draw the walls of one floor. Doors and windows from the library.
- 20–35 min
Name the rooms and read their areas. This is where a plan becomes data, and where students discover that a room they thought was 20 m² is 17.
- 35–45 min
Open a schedule of rooms and a quantity of the walls. Compare two groups' numbers for the same brief.
- 45–55 min
Cut a section. Show the same model as plan, section and 3D on one screen.
- 55–60 min
Export IFC. The file leaves the room with them, and the next session can start by importing someone else's.
02 / FIVE LESSONS
What each lesson asks the student to hand in
| Lesson | Objective | Handed in | Time |
|---|---|---|---|
| 1 · Look and measure | Read a model instead of drawing one: sections, properties, room areas. | One section and three room areas, with a sentence on what surprised them. | 15 min |
| 2 · Levels and walls | Turn a brief into a floor plan with levels that agree with each other. | A one-floor plan with named rooms. | 30 min |
| 3 · Quantities and cost | Get numbers out of the model, and see how a design decision moves them. | A room schedule and a wall quantity, before and after one change. | 30 min |
| 4 · Services and clash | Route a duct and a cable tray, then find where they collide. | A clash check with one clash fixed, and the before/after screenshots. | 45 min |
| 5 · IFC and the AI | Prove the model survives leaving the tool; then hold an AI to account. | The exported IFC, re-imported, plus the agent's own list of what it did not do. | 30 min |
Lesson 5 is the one we would build a course around. A student asks Caddie to model something, then checks the model's own counters against what the agent claims, and reads the answer to "what have you not done?". That habit — verify the agent, not trust it — is the part of AI in construction that is not being taught yet.
03 / COMPETITION BRIEF
One school, 1,000 students
A whole-class brief that fits a term: design an upper-secondary school for 1,000 students, and deliver it as an IFC file. Judged on four things, in this order:
- The plan works. Rooms that a school can actually run, with areas that add up.
- The data survives. The IFC opens elsewhere with names, levels and areas intact.
- Services fit. The clash check has been run, and what it found is either fixed or explained.
- You can say what you did not do. One page listing the assumptions, the parts left out, and the checks not run.
Reference: a curvilinear campus for 1,000 students, modelled in a browser tab — including the structural frame that had to be rebuilt to follow the arcs, and the agent's own list of what it had left undone.
04 / HONEST LIMITS
What to tell your students before they start
- Everything runs in the browser. That is why there is nothing to install, and also why the first load is the slow part. Measured on a six-times throttled CPU over a 2 Mbps connection with 150 ms latency: interactive in 18 seconds, a model on screen in 24. On a normal connection the same path takes 3.4 seconds. Test the worst machine in your lab before you plan a session around it — the numbers above are a simulation of one, not a promise about yours.
- The AI is metered. The app is free; Caddie's credits are not unlimited. Do not build a graded exercise on an agent you have not first run yourself.
- No structural or code verification. Clash checks find geometry that collides, not loads, fire or egress that fail.
- Not an accreditation. Nothing here replaces your course's own assessment, and we do not issue a certificate.
Run it yourself
Nobody here will offer to demo this, sit in on your session or teach the lessons for you. The page, the five lessons and the app are the whole offer: open a link, put a group in front of it, and see whether it is useful. It is free, so trying it costs a session and nothing else.
If something breaks — a lesson that does not work on your machines, a claim on this page that turned out wrong, a number in the limits list that is too generous — write to matsromblad@gmail.com and say so. Those corrections go into the lesson plans, and a report that it is not good enough is as welcome as one that it is.