At some point in a bespoke commission you will be sent an image of a ring that does not exist yet and asked whether it is right. That image is a CAD render, and your reply to it is the most consequential message in the whole project.
Most people read it the way they would read a photograph in a shop window. Do I like it. That is an incomplete question. Engagement ring CAD design is a dimensional exercise as much as an aesthetic one, and the things that disappoint people later are almost always numbers somebody glanced at and did not actually check.
Here is what a render is, what it quietly improves, and the handful of things worth confirming before you approve one.
An Engagement Ring CAD Design Is a Model, Not a Picture
Two different things get shown to you under the same name, and the difference matters.
The first is the model: a three-dimensional object built to real measurements in millimetres, in software of the kind used across the trade — Rhino, MatrixGold, JewelCAD and their relatives. Every part of it is a number: a band 2.1mm wide and 1.6mm thick, claws of 1.1mm, a seat cut for an oval measuring 7.2 by 5.4mm. That model is the specification, and it is what gets printed and cast.
The second is the render: an image generated from the model by software that simulates light, metal and faceting. It is a drawing of the specification, not evidence about it. Rendered brilliance is calculated rather than observed, which means a render can make an ordinary proportion look lively and can make a very good sapphire look flat. Neither outcome tells you much about the ring.
Treat the model as the contract and the render as the illustration. When you approve a design you are approving the numbers, so ask to see them. Any studio working this way can produce them in a minute, because they already exist. At Laher nothing goes into production until you have seen and approved the design, which is worth confirming wherever you are working.
Ask for the Millimetres, Then Measure Something She Already Wears
A screen has no sense of scale. On a laptop, a 6.5mm round stone fills your visual field like a doorknob; on a finger it is modest. Carat weight does not rescue you either, because two stones of the same weight in different shapes cover very different amounts of finger.
The fix is unglamorous and it works. Get the numbers, then go and find them in the physical world. Measure the width of a ring she already owns and wears happily. Mark the stone's length and width on paper and hold it against a hand. Five minutes of this is worth three more rounds of revisions.
These are the numbers to ask for, and what a useful answer sounds like.
- What are the centre stone's actual dimensions? A length, width and depth in millimetres — not just a carat weight.
- How wide and how thick is the band at the back of the finger? Two separate numbers. Width is what you see; thickness is what you feel all day.
- How high does the stone sit above the finger? A profile measurement in millimetres. This is the difference between a ring that slides under a jumper sleeve and one that catches on everything.
- Is the model built around my stone, or a stock shape? If you have chosen a particular stone, the seat should be cut to its measured dimensions rather than to a library gem of roughly that size.
- What finger size is this modelled at? Band width affects fit, so a wider band in the same nominal size will feel tighter.
What the Render Quietly Improves
Renders are perfect, and rings are not. That gap is not deception, it is just what a rendering engine does, but you should know where it sits.
Symmetry in a model is exact. In a finished ring, casting and hand-finishing carry tolerances of fractions of a millimetre, which is invisible in normal use but does mean the object in your hand is not a copy of the file. Claws are the clearest example. In a model they are neat geometric forms standing to attention; on a set stone they have been filed, pushed over the girdle and rounded off by hand, so the finished claw usually reads softer and slightly shorter than the rendered one. If you are still choosing between arrangements, we have written about how four, six, compass and split claws actually behave.
The stone is the least reliable part of the image. It is a generic gem shader: an idealised shape with an idealised colour and idealised light passing through it. If you have already selected a sapphire, the render is not a picture of your sapphire and cannot be. Australian parti and teal material is the extreme case, because its whole character is colour that shifts as the stone moves, and no static image holds that. Look at the stone in the hand, under a few different lights, and use the render to judge the metal around it.
One habit worth adopting: ask for a photograph of the printed pattern before it is cast. A resin or wax pattern costs very little, and holding one settles arguments that four renders will not.
Thickness Is Where Comfort, Durability and Cost Get Decided
The least interesting numbers in the file are the ones that determine whether you enjoy wearing the ring in five years.
Cast metal has a practical minimum thickness. Casting guidelines commonly put the floor for a wall at around 0.75mm, below which sections start to distort. A floor is not a target, though. A band sitting at the minimum is a band that will thin out with wear sooner than one built with a little more in it, and a fine, delicate profile in a render is often a fine, delicate profile in fact. Going the other way, extra thickness adds weight and cost, and there is a point where solid becomes clumsy.
Metal weight is knowable before anything is cast, because the model has a calculable volume. Multiply that volume by the density of the alloy and you have the weight. Pure gold sits at about 19.3 grams per cubic centimetre and platinum at about 21.45, and in practice the same design made in platinum rather than 18ct gold comes out roughly a third heavier — the conversion jewellers use is about 1.34 times. That is a real difference in the metal component of a quote, and it is one of the few parts of a price you can see coming. Our guide to gold, platinum and the alloys in between goes further into how the metals behave.
So ask what the piece is expected to weigh in each metal you are considering. It is a question that separates studios quickly.
Where CAD Approval Goes Wrong, Including in This Studio
We build these renders and we send them to clients, so read what follows as self-interested and test it against whoever you end up working with.
The first failure is approving out of fatigue. Our clients get unlimited revisions — no alteration clauses, no cap on rounds, and nothing goes into production until they are satisfied — which is the right policy and also a trap if you use it badly. A design can be revised into blandness, each round sanding off a decision until what is left is agreeable and anonymous. If the fourth version looks less like her than the second did, say so and go back.
The second is approving an image you cannot actually read. Plenty of people cannot convert a render into an object in their head, and there is nothing wrong with that. Another render will not fix it. Ask for the printed pattern instead, or ask to come in and look at a comparable finished ring. Our jewellers are on the premises in Surry Hills, which mostly matters because it shortens the loop when something needs to be looked at rather than described.
Here is the part that costs us something to write. If you are not sure at the approval stage, the correct move is to stop rather than proceed politely. We would rather hold a project for a fortnight than cast a ring you were quietly unconvinced by. The moment before approval is the easiest point in the whole project to change your mind. Everything after it is metal, stones and hours.
Before You Reply "Approved"
Read the model rather than the picture. Ask for three numbers — the stone's dimensions, the band's width and thickness, and how high it sits — then check each one against a ring that already exists. Ask what it will weigh. Look at the stone in person and let the render argue only about the metal.
Then sit on it overnight. There is no version of this process where a design has to be approved the same day, and if it feels that way, that is worth a conversation of its own. If you want one question to finish on, ask the designer what they would change about it if it were theirs. Someone with nothing to offer has not looked hard enough. Most of what makes a ring feel considered a decade later gets decided in this exact exchange. If you have not yet had the first meeting, we have written separately about what a bespoke design consultation actually covers.
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Laher is a bespoke jewellery studio in Surry Hills, Sydney. We design and handcraft engagement rings and fine jewellery using Australian sapphires and unique coloured diamonds.