ArchiTool Beta
Terrain Analysis & Grading
Upload a site, read its natural drainage, sculpt grading to balance cut and fill, and watch storm response update in real time. Three modes: Flow (read the land), Rainfall (test a storm), Grading (regrade and see what changes).
Water Flow & Rainfall Lab
Bring in a site — upload a survey, pull real elevation from any location, or try a demo — then read its natural drainage. Switch to rainfall mode to overlay storm depth, infiltration, and flood extent.
Load your site
Upload a survey, pull real elevation from anywhere on Earth, or start with a demo.
Search above, or Shift-drag on the map to choose your site.
Identify Design Risks & Opportunities
As you read the overlays, annotate the following to justify your design moves:
About Hydrology·Trace water across terrain and study storm runoff.
What Hydrology does
Upload a terrain grid (DEM) or model and the tool computes flow accumulation, ridges, valleys, and watershed basins. Switch to Rainfall mode to simulate a storm and see where water pools.
- Input:
- .asc / .obj / .3dm
- Modes:
- Flow · Rainfall
- Output:
- Flow lines, basins
How it works
Standard D8 terrain hydrology, the same routing GIS packages use. Depressions are filled with a priority-flood pass first, because an unfilled pit swallows the flow above it and quietly invents a dry valley downstream.
- Priority-flood depression filling before routing, so every cell has a downslope path to the edge.
- D8 flow direction: each cell drains to the steepest of its eight neighbours.
- Flow accumulation and contributing area computed per cell, which is what makes channels and ridges emerge.
- Slope and contours derived from the same filled grid, so the drawings and the analysis agree.
- Grading mode re-runs the whole chain on your edited terrain, so a cut-and-fill can be tested against the flow it changes.
How to use it
- Upload terrain. Drop a .asc, .obj, or .3dm of your site terrain.
- Pick a mode. Flow Mode (drainage analysis) or Rainfall Mode (storm simulation).
- Read the legend. Amber = ridges, cyan = valleys, contours and basins toggle on top.
- Export to Rhino. Download the flow lines or rainfall surface as a .3dm.
Best used for
- Finding where water wants to go across a site before fixing levels.
- Testing whether a proposed regrade moves a problem or solves it.
- Locating ponding risk and the natural low points early.
- Reading a site catchment structure — ridges, valleys, basins — from a DEM you already have.
Not a substitute for
- Drainage design or pipe sizing.
- Flood-risk assessment or any regulatory submission.
- Anything requiring a hydraulic model with roughness, infiltration and time-stepping.
Known limits
- D8 forces all flow from a cell into one of eight directions, so it exaggerates channelisation on gentle, broad slopes.
- The result is only as good as the DEM: resolution, vertical accuracy and vintage all propagate straight through.
- No infiltration, no soil, no roughness, no time — this is where water goes, not how fast or how much soaks in.
- Culverts, drains and anything buried are invisible; the terrain is treated as the only path.
- Depression filling removes real ponds as well as artefacts, which is the trade the method makes.