The project was a mid-block redevelopment in a city with a good GIS portal and a survey that would not arrive until the following week. My job that Thursday was not design. It was to make sure the site model we handed to the Revit team had the right origin, the right units, and enough context to survive coordination. I tested both tools against that job.
The Handoff Is the Real Test
A site model is only useful if the next person can open it without a phone call. That means predictable units, a sensible origin, geometry clean enough to snap to, and a format the receiving tool reads. It also means knowing which parts are measured and which are inferred. Most comparisons skip this and talk about the pictures.
Archshaper: A Map With an Export Contract
Archshaper starts by locating the project area, then lets you control layers: buildings, roads, water, green space. You can restyle those layers and choose from several visual styles. The 2D output is meant for boards, presentations, and project documents, and it stays at true scale. The 3D scene adds terrain and surrounding buildings, enough for early spatial study and massing without pretending to be a BIM authoring tool.
The export side is explicit. 2D goes out as PDF, SVG, or DXF; 3D as GLB, OBJ, or Rhino 3DM. PDF for review, SVG for layout, DXF for CAD, GLB for viewers, OBJ for mesh work, 3DM for Rhino. The preview is free and exports use credits, with no fixed subscription. The trade-offs are clear: browser-only, dependent on underlying map data, and unable to invent what the data never captured.
GenAnywhere: A Generative Face for the Block
GenAnywhere has a smaller interface idea: select a box on the map, let the AI generate a 3D model. It is quick, and the first result often reads well. Roofs have plausible pitches, the street edge feels occupied, and the massing has enough variation to start a conversation. For a review where the question is whether a block wants a tower here, that is a real contribution.
From a pipeline perspective, the output is a generated mesh, not a layered record. You cannot keep roads and hide buildings, and the file does not say which surfaces came from data and which were guessed. Run the same box twice and the geometry can change; small structures appear and disappear. The model also arrives without provenance, so scale and orientation have to be established first.
Units, Origin, and the Ten-Minute Sanity Check
I opened the Archshaper DXF in CAD and checked a curb-to-curb dimension against the survey. It matched. The GLB came into Rhino at a sane size, though I still set units before import because my template defaults to feet. The 3DM opened in Rhino cleanly, which saved time downstream.
The GenAnywhere mesh needed a different ritual. I picked a known building face, scaled the model to it, then checked two other dimensions. The first pass was off. After correction it was usable as a visual underlay, but I would not dimension from it. That is less a criticism than a property of generated geometry. The check is part of the job.
Where Each Belongs in the Pipeline
Archshaper belongs upstream of documentation. It produces the measured base, the layered context, and files that keep their scale when they move. It is where the site becomes an object with a known origin. GenAnywhere belongs beside the design conversation, before the team agrees on a massing. It produces options, not records, which is legitimate as long as nobody forwards it as a survey.
A workflow that worked for us: build the base in Archshaper, export DXF and GLB, then generate two or three massing studies in GenAnywhere. We never merged the AI mesh into the base. We rebuilt the chosen idea on the measured layers, using the generated model as a reference. The Revit team got a clean origin, the landscape team got separate layers, and the renderer got a GLB that did not need rescaling.
What I'd Tell the Next Person
Decide what the file is for before choosing the tool. If it must be measured, opened, and trusted by someone else, start with the layered map and its export formats. If it must be discussed, questioned, and thrown away by lunch, start with the generator. Neither replaces a survey or a designer; they remove two different kinds of waiting.
