Most grading problems surface too late: in samples, in production, in returns.
We catch them before you cut fabric.
The brands with the highest fit‑related returns rarely have a factory problem or a grader problem. They have a grading visibility problem, one that compounds quietly across sample rounds and retail returns before it shows in the numbers.
Nabla Labs solves it upstream. Our closed‑loop simulation tests your graded patterns across a body distribution matching your real customer base, factors in your specific fabric properties, and returns corrected DXF geometry where grading needs adjustment. Fewer sample rounds per style, lower exposure to fit‑driven returns, and a documented grading standard that travels across factories and seasons without changing how your team designs or grades.
Problem
Sizing problems that
are hard to see on paper.
Inconsistent fit between styles erodes customer trust and drives repeat returns, even when your specs look identical on paper.
Edge sizes are where grading breaks most often and where customers notice it most, but they're rarely stress-tested with the same rigour as the base.
Fit decisions today rely on one fit model and one or two physical samples — and every new grader or factory reinterprets the result. Edge sizes, extended sizes, and shape diversity within a demographic stay untested until customers complain.
Single Fit Model
One body validates base size
Static Grade Rules
Same rule applied across all sizes
Size range output
Differentiation
What downstream tools can't see,
and where the problem actually lives.
Size recommendation tools, virtual try‑on widgets, and fit advisors all operate at the same point in the process: after the garment is designed, graded, and produced. What none of them can do is change the pattern. The fit problem they're managing was created months earlier, inside your grade rules. That's where Nabla Labs works.
Traditional fit standards define a representative body per demographic. Pattern is graded against that one body. Useful for setting brand‑level fit identity. Limited when customer shape diversity matters.
We extend body standards with body distributions. Same starting point: your existing fit standards, your size charts. Different unit of analysis: a population, not a point.
Industry-standard fit work picks a single representative body per demographic and grades the pattern against that one body. Garments fit the centroid of your customer base well; the tails fit poorly. Edge sizes, athletic builds, and shape diversity within a demographic all get under-served.
Nabla Labs runs upstream fit validation against a body distribution that statistically represents your target market. The technique, population‑aware grading, tests every size in your range across the actual variance of your customers, identifies where grading breaks, and (with closed‑loop correction) returns adjusted patterns. Same starting point as your existing fit work: your body standards, your size charts. Different unit of analysis: a population, not a point.
Already using CLO 3D or Browzwear? Nabla Labs complements them.
Those tools show you how a garment looks, you still need someone to interpret what the simulation means across your size run and correct the grading. That's what we do.
How it works
How it works.
You send us a graded DXF/CAD pattern set and a description of your target customer. We run a closed‑loop simulation across a population of bodies that match that customer, identify where grading breaks at each size, and return a diagnostic report and an adjusted DXF.
Ingest
Ingests your existing graded patterns (DXF/CAD and ASTM formats).
Analyse
Runs a virtual fit analysis on multiple body shapes across all sizes in the range.
Identify
Identifies tight, loose and unstable areas on each size with clear visual diagnostics.
Report
Produces a structured report you can use with your pattern maker, fit model and factory.
Visualize
Interactive web-based visualizations of simulations with various avatars, easy to watch and interact with, requiring no specialized hardware.
Calibrate
Calibrates the fit analysis to your target customer distribution, not a single fit model.
Correct
Unlike diagnostic-only tools, Nabla Labs uses a closed‑loop simulation engine, one that can compute what the corrected pattern geometry should look like, not just where the current grading fails. Optionally, you receive an adjusted DXF alongside the diagnostic report: a concrete proposed correction your pattern maker can review, refine, and approve. The fix is already in the file.
Outcomes
Results you can measure.
After a Nabla Labs analysis, your pattern maker has concrete notes on where to adjust, not just a feeling that something is off. Your fit sessions focus on the two or three sizes that actually need physical review, not a blind check of the full run. Your operations team has a documented fit standard that travels across factories and seasons. And you go into production knowing your edge sizes behave the way your base size does.
Fewer grading-related sample rounds per style.
Better use of fit model time, focused on sizes flagged as high risk.
A documented grading standard that travels across factories and seasons.
An optional Fit Quality Score per style: a documented, repeatable internal KPI you can track season over season.
Integration
Designed to work with your current team.
Works with patterns from your existing grader, freelancer or factory.
Produces factory‑ready pattern files plus an additional fit report.
Gives technical designers and pattern makers concrete data on where grading breaks.
Helps fit models and fit technicians focus on problem sizes and problem zones instead of checking everything blindly.
Provides founders and product teams a clear view of sizing risk by style.
Grading Risk Overview
FAQ
Common Questions
Who is Nabla for and what are the technical requirements?
Our solution is designed for technical designers, pattern makers, fashion brands and grading houses. We require zero 3D knowledge and no specialized software licenses. It is a low-investment way to bring high-fidelity physics to your existing DXF/CAD workflow.
What is required to integrate Nabla into my current process?
The bar for entry is intentionally low. We only require your DXF/CAD pattern files and grading specs. We hook into your existing workflow without requiring you to change how you design or grade patterns.
How does this compare to 3D tools like Clo3D or Style3D?
Clo3D and Style3D are excellent simulators, but you still need to interpret and act on those simulations manually. We do the interpretation and correction for you. If you already use 3D tools, we complement them; if you use DXF-only workflows, we give you 3D-level insights without the overhead of a full 3D stack. If your team doesn't have the bandwidth to run and interpret 3D simulations in-house, we deliver the same level of insight as a report, without the tooling overhead.
How is this different from Virtual Try‑On (VTO) widgets?
VTO tools manage a symptom. The symptom is a customer who can't find their size. The underlying cause is a grade rule that makes XL fit differently from M, and that cause was set in motion during pattern development, long before the garment reached a product page. Nabla Labs works at that earlier stage: correcting the grading so the inconsistency that would have required a VTO workaround never gets produced in the first place.
Does this rely on Generative AI for the simulations?
No. While we leverage AI for optimizations, our core engine is based on high-fidelity physics. We simulate the mechanical interaction between fabric and body across diverse shapes and dynamic postures on your behalf, sending back corrected grading and clear diagnostic reports.
Which garment categories do you support?
We support virtually all garment categories. We focus on critical functional zones (armholes, crotch, necklines) to identify where grading errors most frequently impact comfort and aesthetics, helping you iterate faster.
How do you generate the bodies you simulate on?
We use our own internal body‑shape model, calibrated against public anthropometric datasets and any size charts or fit standards you provide. We can sample bodies that match a specific demographic (region, age band, athletic vs. standard build) or a custom distribution defined for your customer base. The output is a population of bodies suited to your brand's market, used as the test bed for your patterns.
How do you handle fabric physical properties?
We work with measured properties when available, or estimated properties from descriptions and reference samples. Fabric behaviour is part of the grading decision, not an afterthought. See our Fabric page for how we approach fabric‑aware grading.
If you manage grading or fit, this is built for that problem.
Early‑access participants get access to the tooling, feedback on their own styles, and influence on how the diagnostics evolve.
Pricing per style. Volume and early‑access rates on request.