Both Finch 3D and Fenestra have been showing up in roundups from Coursiv and Architizer for the past six months. We hadn't covered either, partly because neither fits cleanly into the rendering-and-visualization niche that most of this journal covers, and partly because early-stage design tooling for architects is a harder category to review honestly. The claims tend to outrun the reality.
We ran both through real project scenarios over the past four weeks. Finch 3D went through a 48-unit multifamily housing scheme we were in early SD on. Fenestra we tested against a glazed commercial facade we've been analyzing for a client who wants to hit LEED Gold. Here's what we found.
Finch 3D: what it is
Finch 3D is a generative floor plan and massing tool that lives inside Rhino. You define a site boundary, set your program, unit mix, circulation requirements, shared amenity areas, maximum floor plate dimensions, and Finch generates layout options that satisfy the constraints you've specified. Think of it as a constraint-satisfaction engine for residential planning, not an AI in the image-generation sense.
The underlying logic is parametric. You're not prompting it in natural language. You're filling out a structured brief: 24 one-beds, 18 two-beds, 6 three-beds, double-loaded corridor, maximum unit depth of 12 metres, fire egress at both ends of each floor. Finch produces layouts that honour those constraints, then lets you explore variations, swap a double-loaded corridor for a point-access core, increase average unit size at the cost of unit count, try a different building footprint.
Rhino plugin for generative floor plan layout. Best suited to repetitive residential and mixed-use schemes where exploring many layout permutations quickly is genuinely valuable. Not a rendering tool, outputs are Rhino geometry and layout data, not visualizations.
What the free tier actually gets you
The free tier is more useful than most free architecture software tiers, which typically give you a nonfunctional demo. In Finch's case, you can run real projects through the constraint engine and see generated layouts in the Rhino viewport. What's locked behind the paywall is export, you can't push the geometry into your actual model or downstream software without a paid plan. For evaluation purposes, that's fine. For billing time against it, you need the paid tier.
Where it actually helps
On the 48-unit scheme, we ran the program brief through Finch in about 40 minutes of setup. It returned twelve layout variants in a range from 38 to 51 units (the constraint engine finds the maximum feasible count within your site boundary, not just the number you specified). Three of those twelve layouts were genuinely worth comparing in more detail. One suggested a core placement that our team hadn't considered, a central wet wall spine that let us reduce corridor length by about 8% without compromising unit depths.
Finch doesn't design. It searches. The value is in what it finds during the search that you might not have reached in the time you had.
That's the honest framing for this tool: it's a fast search engine for feasible layout space, not a design collaborator. If you're an experienced residential architect, you'll recognize most of what it produces. The value isn't novel solutions, it's speed and coverage. In a two-hour SD session, you can explore layout territory that would take two or three days of manual iteration.
Limitations worth knowing
Finch works well on repetitive unit types. It struggles with anything bespoke. A custom residential project, a cultural building, anything with complex circulation or non-standard program, Finch has nothing to offer. The constraint engine is tuned for housing typologies. Push it outside that envelope and the outputs are either unrealistic or obviously wrong.
The Rhino dependency is also a real constraint. If your practice is Revit-first, Finch doesn't fit your workflow without a translation step. There's no native Revit integration as of this writing. You can export to DWG and trace, but that introduces coordination friction that erodes the time savings.
Fenestra: what it is
Fenestra is a different kind of tool entirely. It's a facade and window optimization platform that takes an existing building model, massing or schematic design, and runs climate-informed analysis on the envelope. The outputs include daylight scores (sDA and ASE), predicted energy loads from solar gain, and, critically, proposed modifications to window placement, size, and shading geometry that would improve your performance metrics.
It's closer to a performance consultant embedded in software than a generative design tool. You're not asking it to design a facade, you're asking it to analyze what you have and tell you where the problems are, with specific recommendations for fixing them.
Facade and window optimization tool with AI-driven daylight simulation. Analyzes window placement, glazing ratios, and shading geometry against climate data and target performance metrics. Outputs sDA/ASE scores and specific modification proposals. Works with Revit, Rhino, and IFC imports.
Testing it on a real performance brief
The commercial facade project was a good test case because we had a specific brief: hit LEED Gold daylight credits, which requires demonstrating sDA of 55% or better across occupied areas. Our initial scheme had a west-facing glazed curtain wall that was generating excessive solar gain, the energy model was showing cooling loads that were going to hurt the LEED scorecard.
Fenestra ingested our Revit model via IFC export in about four minutes. It ran the climate analysis (we're working in Philadelphia, so mid-Atlantic climate data) and returned a detailed facade report inside fifteen minutes. The report identified three problem zones: the southwest corner where solar gain peaked in afternoon, a low-sill condition on the fourth floor that was creating glare without contributing meaningfully to dDA scores, and a shading overhang that was undersized by about 400mm for the latitude.
The recommendations were specific: recess the southwest glazing by 300mm, raise the fourth floor sill by 450mm, extend the overhang depth. Fenestra then modeled the proposed changes and showed the predicted sDA improvement, from 49% to 62%, which puts us comfortably above the LEED threshold. We haven't taken those changes through full detailed modeling yet, but the directional guidance aligns with what our energy consultant was independently suggesting.
The value isn't that Fenestra tells you something you couldn't figure out yourself. It's that it does it in 15 minutes, with specific numbers, before your energy consultant bills you for three hours of simulation work.
Limitations
Fenestra's analysis quality depends heavily on the fidelity of your input model. Feed it a rough massing model with generic window geometry and you'll get directional guidance but not precise numbers. For early SD it's useful as a rough screen. For DD-level accuracy you need a detailed model, at which point you're probably also involving your energy consultant directly.
The climate data library covers major metro areas well, but if you're working in a complex microclimate, coastal, high altitude, dense urban canyon, the standard climate files may not capture what's actually happening at your site. Fenestra doesn't yet support custom climate file uploads on the base tier.
Structural and constructibility logic isn't in scope. Fenestra will propose shading geometry that improves daylight performance without considering whether that geometry is cost-effective to build or structurally sensible to attach. You're still doing that judgment yourself.
Side by side: where each fits
| Dimension | Finch 3D | Fenestra |
|---|---|---|
| Design phase | Pre-SD / early SD, before form is fixed | SD through late DD, after form exists |
| Best project type | Repetitive residential, multifamily, modular | Any glazed building with performance requirements |
| Tool dependency | Rhino required | Revit, Rhino, IFC, wider compatibility |
| Free tier usefulness | Strong for evaluation, full constraint engine, limited export | Good, limited analyses per month, no custom climate files |
| Learning curve | Moderate, constraint setup requires structured thinking | Low, mostly model import and parameter review |
| Output type | Rhino geometry (floor plans, layouts) | Performance reports, annotated modification proposals |
| Replaces consultants? | No, replaces some manual layout iteration | No, screens before engaging energy consultant |
Who should try each one
Finch 3D is worth serious evaluation if you're a housing architect doing repetitive unit-count work in Rhino. The free tier is enough to run a real project through and see whether the layout search adds value to your process. If your practice doesn't do repetitive residential, skip it, the tool won't reshape to your workflow.
Fenestra is worth trying for any practice that regularly deals with daylight or energy performance requirements, LEED, BREEAM, Passive House, or just clients who ask about energy early. The freemium tier's monthly analysis limit is genuinely limiting for a busy practice, but as a first screen before you involve a specialist consultant it's hard to argue with the time savings.
The interesting thing about covering both tools together is that they're not competing for the same problem. They address completely different moments in the design timeline. A practice doing well-considered multifamily housing with a sustainability brief could plausibly use both, Finch in the first week to explore layout options, Fenestra three weeks later once the chosen scheme has enough envelope geometry to analyze. That's a useful mental model for where each one lives.
Neither is essential. Neither is hype. Both are solving real, specific problems faster than the manual alternative, which is the only standard worth applying.
Tested by Vista Studios on live SD-phase project work. No affiliate relationship with Finch 3D or Fenestra. Finch 3D tested on 48-unit multifamily scheme in Rhino 8. Fenestra tested on a commercial glazed facade project with Philadelphia climate data.