XO3D Studio · Technical guide
CAD to CGI.
CAD describes how a product is made. CGI has to describe how it looks and feels, to someone deciding whether to buy it. Those are different jobs, and the gap between them is where most technical product visualisation goes wrong. This is what actually transfers, what breaks on the way, and what your engineering team should send.
The studio behind this guide
When the CAD pipeline is our work
XO3D builds production CGI directly from client CAD, and an engineering review of the supplied geometry happens before the model is scoped. Come to us when the source data is real engineering geometry and dimensional accuracy has to survive into the finished frame. One limit worth stating up front: a model built from your CAD is not an engineering sign-off and cannot certify a tolerance.
How XO3D compares to the other five supplier modelsFormats
What we
work from.
If your format is not listed, ask. Most engineering formats are workable, and the honest answer about yours takes one look rather than a meeting.
| Format | Software | Notes |
|---|---|---|
| STEP (.stp, .step) | Universal CAD interchange | Preferred. Preserves geometry and assembly structure. |
| IGES (.igs, .iges) | Universal CAD interchange | Common alternative to STEP. Workable in most production pipelines. |
| SolidWorks (.sldprt, .sldasm) | SolidWorks | Native files preserve full assembly hierarchy and material assignments. |
| Rhino (.3dm) | Rhinoceros | Common in industrial and product design. Direct import. |
| Inventor (.ipt, .iam) | Autodesk Inventor | Native engineering files for mechanism and assembly work. |
| OBJ, FBX, 3MF | Generic 3D formats | Workable as a fallback when CAD source is not available. |
Five real problems
Where the
pipeline breaks.
None of these is a reason not to work from CAD. All of them are reasons to know about them before the model is built rather than after the first review.
Exact surfaces have to become polygons
CAD describes a curve as mathematics. A renderer needs triangles. That conversion, tessellation, is where a beautifully engineered fillet turns into visible faceting on a hero close-up. It is a production decision rather than an import setting, and it has to be made per part, at the resolution the final shot needs.
Assembly structure gets flattened
Exported CAD often arrives as one merged object. If the brief involves a mechanism opening, a part separating or an exploded view, that hierarchy has to be rebuilt before anything can move. Native files and a well-structured STEP export preserve far more of it, which is why the format you send matters.
CAD carries no usable appearance data
Engineering colour assignments are for reading the model, not for photography. Every material gets reconstructed from physical reference: the actual finish, the grain direction, the anodising, the soft-touch coating, how the paint behaves at a grazing angle. This is the largest single difference between a render that reads as real and one that reads as CAD.
Everything is in there, including what nobody sees
A production assembly contains fasteners, brackets and internal components that will never be visible. Left in, they slow every frame for no benefit. Taken out carelessly, something shows through a gap in a shot nobody anticipated. Deciding what to keep is part of the build.
Concept-stage geometry keeps moving
For a product still in development, the CAD you send is not the CAD that ships. That is normal and it is workable, but it means the 3D build has to be version-controlled alongside engineering rather than treated as a one-time handover. Fundamental changes to a mechanism are a scope conversation, not a silent absorption.
The gate that matters
Engineering
reviews the
model first.
Before any material, light or camera is added, your engineering team reviews the 3D model. Nothing else in the process protects a technical project as effectively, and skipping it is how a beautiful render of the wrong revision reaches a launch page.
What that review catches is specific: the wrong product version, an assembly relationship that does not reflect the real mechanism, a component at the wrong scale, geometry simplified somewhere it carries meaning. All of those are cheap to fix at model stage and expensive once lighting, animation and multiple formats are built on top.
It needs one named person who can say yes. A review circulated to a group without an owner tends to come back as silence, which is the most expensive answer available.
Be precise about this
What accurate
does and does
not mean.
A model built from your CAD and confirmed by your engineers is a strong basis for a technically credible image. It supports a claim that the visual reflects the product as designed and as reviewed.
It is not a validation of the manufactured product, it is not an engineering sign-off, and it is not a regulatory approval. A render cannot certify a tolerance and should never be presented as though it does.
Where a specific accuracy or representational requirement exists, particularly on medical, industrial or safety-related products, define it at brief stage and name who approves it. That is a short conversation before production and a serious problem afterwards.
Before you send anything
The five things
worth gathering.
- The best CAD you have, in the best format you have
- STEP is the safest default. Native SolidWorks, Rhino or Inventor files preserve more. If the geometry is at concept stage, send it anyway and say so.
- Material and finish specifications
- Not colour names. The actual finish: anodised, powder-coated, soft-touch, brushed, and in which direction. Physical samples are better than any document.
- Engineering drawings where they exist
- Dimensions, tolerances and assembly relationships resolve ambiguity in the model far faster than a conversation about it.
- The mechanism sequence, if something moves
- What moves, in what order, and how far. A short video of a prototype, however rough, is worth more than a description.
- A named technical reviewer
- One person on your engineering side who can confirm the model is right before materials and lighting are built on top of it. This is the single most valuable thing you can supply.
Confidentiality comes first if the product is unreleased. How CAD is handled, who can open it and how long it is kept is set out on trust and security.
Related
Where to
go next.
Common questions
Technical
answers.
What CAD format should we send for CGI?
STEP is the safest default, because it preserves geometry and assembly structure and is readable by every production pipeline. Native SolidWorks, Rhino or Inventor files preserve more, including hierarchy and material assignments. IGES is a workable alternative. OBJ, FBX and 3MF can be used as a fallback where no CAD source exists, though they arrive with less structure to work from.
Can you work from CAD that is not finished?
Yes, and much of the most useful work happens exactly there. For a product still in development the 3D build is version-controlled alongside engineering, so design changes can be brought in as they happen. Minor revisions such as a material change or a component adjustment are usually absorbed efficiently. A fundamental mechanism change is a revised scope conversation, and we raise that at the time rather than at delivery.
Does CGI from CAD mean the render is dimensionally accurate?
It means the visual model is built from your supplied CAD and reviewed by your engineering team before production continues. That is a strong basis for a technically credible image. It is not a validation of the manufactured product, and it is not a substitute for engineering or regulatory approval. Where a claim depends on accuracy, define the requirement at brief stage and name who signs it off.
Why do materials have to be rebuilt if the CAD already has colours?
Because CAD appearance data exists to help engineers read the model, not to survive a camera. A real finish behaves in ways a colour assignment cannot describe: how anodising shifts at a grazing angle, how a soft-touch coating scatters light, which way a brushed grain runs. Materials get reconstructed from physical reference, and that reconstruction is most of the difference between a render that reads as a product and one that reads as CAD.
What if our CAD is enormous?
Large assemblies are normal for industrial and engineered products. The work is deciding what is visible in the shots the brief actually needs, retaining the geometry that carries detail at close range, and simplifying what will never be seen. Send the full assembly rather than a guess at what matters, and that decision gets made against the shot list.
Start with the files
Send us what
you have.
Tell us the format, the stage the design is at, and what the visuals have to do. We will tell you what is workable and what is missing.
Send us your CAD questions