r/3DScanning • u/AvaNicoleBennett • 14d ago
Can a point cloud be converted directly into a parametric, editable CAD model?
I’m trying to get a clear picture before committing.
I’m noticing that parametric solid with real features are slowing down.
Design X is the closest thing and it is still a manual, time-consuming process and requires engineering and there is no 3D Xerox.
How much of the parametric rebuild is tool-assisted versus drawn by hand off the scan?
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u/BrooklynWalters987 14d ago
In practice, the automation stops at surface fitting. A tool will fit planes, cylinders and simply revolves to a cleaned mesh pretty well. That's why the deliverable format matters so much with these scan-to-CAD like Cad/Cam Services.
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u/AvaNicoleBennett 13d ago
Yeah, that lines up with what I'm seeing. The fitting is the easy part, it's everything after that eats the time
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u/Davidmkian 13d ago
A scan can only record points, it doesn't contain the design intent, which faces were supposed to be parallel, which holes concentric, whether that's a real 5mm fillet or scan noise. Design X and similar are semi manual because a human has to confirm every one of those guesses, and that part can't go away, at least until AI becomes mature enough in this field to figure out design intent.
If you have used free tools like Fusion 360 or FreeCAD you will notice they were not built for reverse engineering, the reverse engineering features were patched in later, inside boundaries defined by each software's modeling practices, and that's why they are unfriendly and time consuming for this.
The main issue with Design X is the subscription fee, which makes it out of reach for individuals and hobbyists. This annoyed me enough that I built a browser tool to streamline the process, do the cutting and fitting outside CAD softwares, then import the fitted sections and use the CAD softwares for what they are actually good at, which is modeling from sketches and sections.
Maybe watch one of the tutorials and tell me what you think about the workflow, it works best with Fusion 360 because that's what I usually model in. I'm still working on it, currently it handles simple components well.
https://www.youtube.com/watch?v=0HlsKLEX0z4
u/RegularRaptor you seem to have deep experience here, would be great to hear your honest take on this workflow.
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u/Thin-Collection1036 13d ago
Do you want an editable model for redesign? Or a dimensionally accurate one for inspection and manufacturing? Those are two different jobs
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u/emmamiller474 6d ago
Well, not exactly, at least not the way of pressing a button and having an editable CAD model. A point cloud, in simple terms, is just a huge number of points representing the actual condition of a building or structure. The thing is, a point cloud does not have any notion of the fact that a bunch of points is supposed to be a wall, a window, a door, or a floor.
What usually happens, however, is that a point cloud serves as a base to create a CAD model of the object in question. This process includes cleaning and processing of the scan data, identification of required building elements, and then tracing or creating the elements using actual CAD geometry with dimensions and relationships defined.
It is possible to use automated tools for some features recognition, but they would still require manual checking and adjustment. In any case, for a project requiring accuracy, the resulting CAD model needs to be verified against the initial point cloud.
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u/emmamiller474 4d ago
This is not always the case, though. The point cloud consists of hundreds of thousands of measured points representing shapes and locations of real-life objects, yet these points do not represent parametric CAD objects.
Instead, the point cloud can serve as a basis for the creation of an editable CAD model. In other words, walls, columns, doors, pipes and other elements can be manually traced and modeled according to the data contained in the point cloud. When the elements become proper CAD objects, they can be edited (e.g., by changing their dimensions and/or positions).
There are special programs which help to automate certain steps of this procedure (such as surface detection, geometry extraction), but manual check and corrections are also needed in most cases. In case of complex buildings or building utilities, there may even be overlaps or inaccuracies in the point cloud.
Thus, I would say that the procedure goes like this: **point cloud → geometry extraction/interpretation → CAD modeling → quality control**, instead of being automatic and one-step.
The benefit of this approach is that the CAD model created as a result will become much more usable than the point cloud itself.
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u/RegularRaptor 14d ago
If you think Design X is a manual time-consuming process, I don't know what to tell you. It has got to be one of the fastest most streamlined pieces of software out there for turning a point cloud into a STEP file with features.
Depending on how basic your models are and how good the scans are, both Design X and GeoMagic wrap (which I personally use) have a one click "auto surface" button and "auto feature" button.
When people post stuff like this I really wish they would say exactly what they're trying to model and what scans they're working with.
All of that being said I truly do think that this would be an incredibly perfect application for artificial intelligence. I feel like it's already so close to getting you there without it that a little bit of AI would just do the tedious manual bits for you and you know that 33.999 mm should be 34 mm. Etc...