All three are called "3D", but one records motion, one serves the surgical process and one looks at the skin. Comparing their specifications side by side usually leads to the wrong conclusion.
1. 4D: turning expressions into a sequence
The MVS-C4D uses infrared imaging and a three-module structure, with 3D measurement accuracy of ±0.1mm and a capture frame rate of 16fps. It records changes in facial soft tissue during dynamic processes such as smiling, speaking and swallowing. What it outputs is not a single static model but a sequence with a time dimension.
The difference from static 3D is not "more accurate" but "one more dimension": static scanning answers "what it looks like now", while 4D answers "how it changes in motion", which is what orthodontics, orthognathic treatment and cleft lip and palate follow-up care about more. Sequence data is larger in volume and requires frame-by-frame review, key-frame extraction and multi-model temporal comparison. For the trade-offs and data costs of the two, see How to choose between 4D dynamic scanning and 3D static scanning.
2. Intraoperative: comparing during the procedure
The MVS-N1 is a mobile floor-standing unit that uses non-contact high-frequency structured-light scanning, with 3D measurement accuracy of ±0.2mm and a whole scan of less than 9 seconds. It is used in treatment rooms or surgical areas: the preoperative design model and the current form are viewed together for the surgeon's reference.
The value of intraoperative scanning is "checkable at any time", not "predicting the result". The device provides comparison data on form; whether and how to adjust remains the surgeon's decision. External descriptions should avoid commitments such as "precisely predicting surgical results".
The mobile form places extra demands on the site: aisle width, door width, power outlet locations and the sterile boundary beside the surgical area. These need to be confirmed before installation.
3. Skin: 3D plus multispectral imaging
ZETTA combines 3D imaging and multispectral skin imaging in one desktop device: 3D measurement accuracy ±0.2mm, volume measurement accuracy ±0.1ml, whole scan under 25 seconds and a single scan of 3 seconds. The 3D skin analysis system provides skin feature marking, temporal comparison, manual region outlining, independent analysis of local features and report output.
It answers "how the skin condition changes" and does not draw conclusions about treatment results. The report presents images and quantitative indicators; the related judgement is a medical act and should not be made by the device or the software.
4. How the three differ
| Dimension | 4D dynamic | Intraoperative scanning | Skin analysis |
|---|---|---|---|
| Capture target | Facial soft-tissue movement | Facial form in the surgical area | Skin surface, pigmentation and texture |
| Time dimension | Continuous sequence | Several intraoperative time points | Several time points before and after a course of treatment |
| Core output | Dynamic model and key frames | Comparison of the design model and the current form | Images, local indicators, reports |
| Typical device | MVS-C4D | MVS-N1 | ZETTA |
| Typical software | 3D digital facial scanning system | 3D digital plastic surgery system | 3D skin analysis system |
5. Three common misconceptions
"4D is more accurate than 3D." 4D adds a time dimension, not a level of accuracy. The MVS-C4D has a 3D measurement accuracy of ±0.1mm, on par with some static models.
"Intraoperative scanning can predict the result." It provides comparison data between the current form and the design model, helping surgeons make intraoperative judgements; it does not promise postoperative results.
"Skin analysis equals diagnosis." Skin analysis outputs images and quantitative indicators for communication and records; diagnosis and treatment decisions are made by physicians.
Related pages: MVS-C4D, MVS-N1, ZETTA, 3D digital facial scanning system, 3D digital plastic surgery system, 3D skin analysis system.
This article describes applications and does not constitute medical advice; specific parameters, functions and scope of application are subject to the corresponding model's function list, manual and contract.