Restored your unsent plan from .
On a phone? Review your studies
The best thing to do here is open a past study — the replay, the figures and the method statement all read well on a small screen.
Starting a new study works below too, but tracing a site and drilling into the plan is much easier on a larger screen.
Start your study
Four ways in. They all end up in the same place — a site with your structures on it — so use whichever matches what you have in front of you.
Add drawings & detail
one plan · one site · one method. The map has the where; this step adds sizes the satellite cannot show.
The map has the where.
The map has the where. This step adds the how big — the height, diameters and wall thickness no satellite image can show. Drop a GA, elevation, framing plan or section sheet and the assistant reads the figures off it against the structures you have already placed; each one arrives on the next screen as a suggestion beside its field, naming the sheet it came from, for you to accept or reject. Nothing you placed gets moved or replaced.
A framing plan is worth dropping even if you have the heights: it shows the column grid, and without it the grid is guessed from the footprint — which sets how much floor each column carries, and so how big every column is.
Nothing placed yet? You can describe the job here instead and the assistant will place structures from your words — but it has to guess where they are, so setting the site on the map first is the accurate route.
Not sure where to start? These pre-fill the assistant with a typical job — change the location and sizes to match yours.
Describe your job — the AI sets it up
Tell the assistant what is being demolished, roughly where, and how — it asks what it needs, then pre-fills the plan for you to confirm. It helps you plan and simulate; the blast / charge design stays with your licensed engineer.
DEMSIM_LLM_BASE_URL=https://api.ppq.aiDEMSIM_LLM_API_KEY= your ppq.ai keyDEMSIM_LLM_MODEL=claude-sonnet-5(or any vision-capable model)
DEMSIM_LLM_API_KEY —
not DEMSIM_API_KEYS (that's the login password). Until
then you can set up your site by hand just below — it runs exactly
the same simulation.
IFC checklist — non-catalog buildings
A building that is not a regular catalog frame,
or a dropped drawing set, is an IFC job. Export from Revit,
Tekla or Blender (Bonsai). /assist is not an MCP
tool. Every SI number is on a user file or marked assumed.
You did not write a confirmed chip.
- Every SI number is on a user file or marked assumed
- No invented typicals presented as measured
- No charges, holes, delays
- Deliverable is IFC
- Only IfcColumn / Beam / Slab / Wall / Footing
- Openings logged, not pretended as voids
- Rebar assumed unless the file or schedule gave a ratio
- Local metres only
- You did not write a confirmed chip
Your site: boundary & structures
Find your site
Paste a Google Maps link or coordinates and the satellite jumps there. This is the fastest way in — everything else on this screen builds on the view you land on.
Put the structures on the map
Add what is coming down and the neighbours that matter — the surroundings are what turn a collapse into a clearance answer. Every value lands as an assumption you confirm next.
Click the BASE of a structure, never its top. (why?)
Satellite imagery is corrected for the ground, not for tall objects: a chimney is photographed at an angle, so its top leans away from the centre of the image and can appear tens of metres from where it actually stands. Pin the base — the point where it meets the ground — and the model will sit on the real one instead of beside it. If the lean is severe, the Basemap list offers other captures of the same ground; one of them will be closer to straight down.
The assistant reads position and footprint off the imagery. A top-down view carries no height — add that yourself or drop a drawing. Everything it places is an assumption to confirm.
Street View
A viewing aid for judging height and surroundings — every engineering number still comes from your inputs.
Import instead — coordinates, GeoJSON, an IFC model or drone footage
From drone footage (beta)
Pick 3+ overlapping drone photos of the site and the platform sends them to your own open-source photogrammetry node (OpenDroneMap) to build a textured 3D site mesh — stored with the study and downloadable. The capture becomes scenery in the photoreal render, and it can propose structures with measured heights for your plan — every proposal is an assumption you confirm, and anything that is really vegetation or parked plant can be deleted. Greyed out until a NodeODM endpoint is configured on the server.
What is on your site
Nothing placed yet.
Parametric Structures — manual dimensions
Name it, drop it on the map, then give the dimensions the satellite cannot see. The imagery shows the footprint; the simulation needs the vertical size, which only you or the drawings know.
Confirm every assumption
These are L0 typology defaults, not documents.
These are L0 typology defaults, not documents. Edit storeys, storey height and concrete grade to what you know; upload drawings later to raise the fidelity tier.
Put the drawing on the map
This site is in the drawing's own metres, so there is no satellite behind it yet. Pick the same TWO structures on the drawing and on the satellite and everything else follows — the drawing's measured spacing is kept exactly, because every structure moves through one transform.
Two points, not one, and why it can refuse.
Two matched points give the rotation as well as the position, so no north arrow is needed. More importantly they give something to CHECK: a survey drawing already carries true metres, so honest pins must imply a scale of about 1.0. If they imply 1.2 you have clicked the wrong feature, and that 20 % would otherwise ride silently into every clearance in the study. One pin plus a north arrow cannot be checked at all.
📄 Drawings & documents
Checking what is held…
A satellite image cannot see height, so unless you state it, it is a default.
Drop a GA, elevation, framing plan or section and the assistant reads the height, diameters, wall thickness and the column grid off it — each figure arrives beside its own field for you to accept or reject. Nothing you placed is moved or replaced, and every file stays with the study, so a client asking "where did that height come from?" gets the sheet.
Reading figures
off a sheet needs the AI reader, which is not switched on for this
deployment — drop the files anyway and they are kept with the study,
but you will need to type the height and diameters in below. (Running
locally? demsim serve asks for the gateway settings on
first start.)
Member schedule (optional) — beam & column sizes, tier L2
This is a different thing from the drawings button above. Above reads the overall dimensions of a structure off a GA or elevation — height, diameters, wall. This reads a member schedule table — the mark/size/grade/rebar list for a framed building's columns and beams — and is what raises the study from L0 (typology defaults) to L2 (documented members). A chimney or cooling tower has no member schedule, so this does nothing for a stack.
Paste the schedule table text, or upload a photo / screenshot of the drawing sheet — with an AI reader configured on the server (ppq.ai or Anthropic key) the image is transcribed automatically. Every extracted field keeps its verbatim text with a confidence score — doubtful cells are highlighted; click any cell to correct it. Corrected fields re-parse at full confidence; uncorrected doubtful fields are skipped at run time, never silently trusted. (PDF: export the schedule page(s) as PNG/JPG first.)
Proximity to surroundings
Reference rings (inner yellow, outer green) around the selected structure (click one on the plan) — or tick Ring all chimneys to ring the whole row at once — and the measured closest-approach distance to every other structure and receptor — the figures that drive the exclusion-zone radii and the fall direction (plan the fall away from the nearest receptors). Trace neighbouring footprints on the site map, and add receptors (nearby buildings / sensitive sites you only need the distance to). Distances are straight-line, in metres, in the shared map frame.
These are measured clearances — the corridor is swept round the compass and checked against every structure and receptor you have placed. It scores clear air only: it knows nothing about site access, buried services, overhead lines, where the cut can physically be made, or your client's constraints. A suggestion for the engineer, never a decision.
Demolition plan
Review & run
Last look before it goes. Nothing here changes the demolition — it sets how carefully the study is computed and how long you wait.
Before you run — reality check
What is confirmed, what came from map/file data, and what is still a typology assumption for this target — so you know exactly what fidelity you are presenting.
How good does this need to be?
Draft is a fast geometry preview — the reinforcement does not engage, so it does NOT answer whether the structure comes down. Presentation runs the reinforced-concrete hinge and is the setting a study is judged at.
Same physics either way, but not the same reinforcement behaviour.
A cut hinge is reinforced concrete: the bar should yield and hold while the section rotates. At Draft a joint stretches about 50 mm elastically before the steel yields, so the base opens into separate blocks and the shaft tips like a rigid pole — at Presentation that is about 5 mm, roughly ten times more plastic hinge rotation per unit of stretch, which is what real RCC does. Use Draft to plan and iterate; use Presentation before you judge how the hinge behaves or show a client. The run-time estimate below follows whichever you pick.
Detail level & compute
How finely the structure is divided into blocks — nothing else. Finer means smaller fragments and a more realistic debris pile, and the run grows roughly with the cube of it. Applies to chimneys and cooling towers.
This is not the control that makes the reinforcement engage. Element size does not change whether a joint behaves like reinforced concrete or like a stack of blocks — that is Finish quality on the technique screen, which moves the stiffness scale. Raising element size to get hinge behaviour buys a much longer run and none of it.
How long, and where
Ends the run shortly after the structure touches down instead of simulating the rubble settling. Measures which way it went, how it rotated, where the top landed and what it struck on the way — not the final pile. Typically about half the run time on a tall stack.Reference is the engine every capacity test and golden run locks — deliverables run on it. The Bullet preview trades fidelity for speed (joint capacities collapse to one scalar): a quick look-see, never a client figure. Greyed out when this server does not have the preview engine installed.
A collapse is chaotic, so one run is one sample of it. Running the same plan several times over the capacity model's own stated scatter shows how far the debris figure actually moves — a range to plan against instead of a single number. Each run is a full simulation, so 5 runs takes about five times as long. The band covers the capacity model only: not an untested batch of concrete, not the weather, not a charge that fails to fire.
Extras
Timing optimiser
Searches your event timings for the tightest debris footprint, keeping your plan as the baseline so the result can never be worse than what you submitted. It searches when elements leave — never a charge quantity.
Cost: this runs the full simulation 10 times. Expect roughly 10× the wait.
Engineer-mode physics
Preview-speed scaling of stiffness only — failure loads are invariant to it (engine guarantee). But at the default preview value the collapse motion is quasi-brittle: reinforced-concrete ductility under-mobilises and crushing stays dormant, so the fall looks a little more brittle/violent than the physics supports. For presentation-fidelity kinematics, raise it toward 0.3–1.0 (slower to compute).
Building your simulation…
Waiting for a worker to pick this job up…
- Job
- –
- Status
- queued
- Elapsed
- 0 s
- Time remaining
- –
- Model size
- –
- Queue depth
- –
The queue
Everything this server still has to get through, in the order it will take them. Stop anything you no longer need and the jobs behind it start sooner.
Progress is the worker's own step counter and a time remaining measured from this run's actual speed on this server — not a synthetic bar. You can stop a run at any point; nothing else is affected.
My studies
Every simulation this instance has run. Open one to see its replay and figures again, or to file the real demolition footage against it once the job is done.
Project plan — method statement & programme
Results
Records the replay above exactly as you see it.
Records the replay above exactly as you see it — solver output on the satellite view — straight to a file on your machine. Nothing is uploaded and it costs nothing. Set the camera angle you want first; the recording follows the view. For a lit, shaded cinematic version, use the photoreal render below.
Photoreal video
A lit, shaded MP4 of this collapse, rendered on a GPU — a visualisation of the simulation (render adds light, never motion). A premium GPU step; the in-browser 3D replay above is free.