Issue #1,078 | Happy New Year! | January 11, 2021
From the Editor
This week marks the 30th anniversary of me leaving my post as senior editor at CADalyst magazine (the very first publication for CAD users) to strike out in 1991 on my own as a freelance technical writer.
It seems to have worked out. Thank you to all who over the years supported and encouraged me!
We start of the new year with two CAD guys talking about which kinds of 3D design software lets us get 2D plans from 3D models. Paul Cotton is a software engineer from England who sometimes wishes he were a CAD draughtsman: “I like computational geometry and secretly wish all CAD was still done through coding.”
Ralph Grabowski is a ex-civil engineer from Canada who sometimes wishes he still were a manual drafter: “But I like writing better.”
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Paul Cotton: I've seen your YouTube videos on nanoCAD and managed to track you down.
Does nanoCAD wrap much of the C3D toolkit? I come from a Rhino background and I wanted to use it to replace AutoCAD completely, because my workflow starts in 3D with Rhino anyway. However, I don't think Rhino has a very good underlying 3D engine, because I want to take cross-sections of the 3D geometry to produce 2D elevations and cross-sections accurate enough for engineers to fabricate the metal substructure required for forms.
I researched further, found the C3D toolkit, and thought it would easily be powerful enough to import the geometry from Rhino so that I then could set to work on a detailed model. Of course it's very low level, but I'm a software engineer so I'm used to C++, but even so, that's not gonna be a quick job.
Anyway, up pops nanoCAD! I saw video where the Russian head developer said they swapped out the kernel for C3D and so everything looks very exciting indeed! Please enlighten me further.
Ralph Grabowski: The issue at play is that there are two types of 3D modeling, surface and solid.
Rhino is a surface modeler, making it suitable for fast, conceptual modeling in 3D. With it, you concentrate on how things look. So, it cannot do sections, because there is no "inside" to surface models.
(Within surface modeling, there are two approaches: the older one based on polyfaces, and a newer one based on meshes.)
nanoCAD is a solid modeler, which is why it can cut sections, handle constraints, determine physical properties, generate 2D drawings from 3D models, and so on. With solids, you concentrate on how things work, how they will be built, and so on.
(Within solid modeling, there also are two approaches: older history-based modeling, and a newer direct modeling.)
Typically, architects do their conceptual design in Rhino, then move the model to a solid modeler to do the detailed design, analyze the building structurally, and generate 2D plans.
Some CAD programs, like AutoCAD, handle both types of surface modeling and both kinds of solid modeling.
You are right: NanoSoft switched its solid modeling kernel and constraint system to the one from C3D Labs. So in nanoCAD Pro V20 you get:
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The older polyface surface modeling, but not modern mesh (surface) modeling
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History-based solid modeling
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A start to direct modeling (not yet fully developed)
Whether nanoCAD does more kinds of 3D modeling depends on (i) the functions C3D Labs adds, and (ii) the functions Nanosoft chooses to expose. This is the same for any 3D CAD program, no matter which kernel it uses.
nanoCAD uses DWG as its file format, so it can read drawings and models from other DWG editors like AutoCAD, but things are a bit different when it comes to 3D models.
It might or might not read 3D models from other DWG systems, depending on which kernel they employ. In some cases, you might get only a "proxy," a visual representation of of the 3D model. (This can be the same for any DWG editor importing a 3D DWG file from another system.)
Best thing is to download the 30-day demo of nanoCAD Pro 20 to see if it does what you need. Now, it is a bit peculiar, in that it is very powerful in some areas that other CAD programs don't handle, and lacking in others. It depends on your needs; see if it is suitable for you. Certainly, the price is attractive.
Paul Cotton: I knew of the distinction between surface and solid modeling, hence I wanted to get geometries out of Rhino and into a solid modeler ASAP.
When it comes to history vs. direct I am far less clued-up. When you say history, I am guessing you mean parametric like Solidworks and I love that sort of thing. But direct is alien to me.
I downloaded nanoCAD but it doesn't seem to work. I raised a ticket with support and they responded, so I sent a screenshot. Heard nothing since. Will have to wait and see. It looks a bit 2D-centric for my tastes, even the 3D version, but again, I will have to see.
I like modeling in code. I hope direct modeling doesn't take that away altogether.
I wish someone would get a good BIM [building information modeling] alternative to Revit. I detest it, and Autodesk. But that's another story.
Ralph Grabowski: Direct editing is what it means: you directly interact with the 3D model. For instance, draw a circle on the face of a cube, pull the circle out to make a cylinder, or push it in to make a hole.
No one is going to make a replacement for Revit, such as the 30+ replacements that exist for AutoCAD; it’s just too complex. But there are BIM alternatives to Revit from Vectorworks, Bricsys, Graphisoft, and so on.
Paul Cotton: Oh I see, direct editing is push-pull and direct placement. I think the thing I'm interested in is called “geometric dimensioning and tolerances”.
I still don't entirely understand how a 3D surface modeled geometry gets to 2D engineering drawings without a solid modeler. I guess this is covered in the world of CAM [computer-aided modeling] instead of CAD.
Well maybe it isn't CAM, because that's more about machining, but either way, the leap from Rhino to a set of accurate 2D engineering drawings is still fuzzy. At least it is for the facade industry where I work and I know for a fact nothing like Solidworks is used there.
Ralph Grabowski: Tolerancing is available in 2D drawings as GD&T, although in my time as an engineer I never used it. In 3D, there also is PMI (product manufacturing information).
I think what you want is parametric modeling: here you use formulas to determine the size and positions of objects in drawings through 2D dimensional and geometric constraints. Some CAD programs, like nanoCAD Pro, even do 3D geometric constraints, although these tend to be used mainly for positioning parts to make assemblies.
This tutorial on making 2D drawings from Rhino seems useful: studiorola.com/tutorials/2d-illustration/tutorial-making-2d-technical-drawing-using-rhino-3d-part-1/. SketchUp has an add-on LayOut module for generating 2D drawings from its 3D surfaces.
But solids are preferred, as intelligent cross-sections can be generated in 2D from 3D solids, complete with hatching, interior details, and associativity — make a change to the 3D model, and the 2D plans update automatically.
Paul Cotton: In the end, nanoCAD didn't work on my PC, because I had the QT libraries installed. I contacted support and they were keen to help, but couldn't get their heads round the fact that it's OK for me to have QT on my PC if I want to.
And in Other News
Wikifactory is working with $4.5 million in funding to offer an online MCAD collaboration site that handles assemblies, real-time exploded views, and commenting. After opening in beta last year, the site hosts three thousand projects with 70 thousand members.
The "Wiki" half of the name means that you can invite people to help you work on designs, although it appears that at this point you can only view and comment on designs, not edit them. The "factory" half involves manufacturing the designs, although it is not clear to me whether that function is up and running yet. wikifactory.com
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In a first, Graphisoft releases a mid-release update to ArchiCAD 24 to add to its new emphasis on integrated design. With parent Nemetschek Group hosting so much disparate technology, the pieces are starting to be put together without the need for IFC translation; instead, data flows directly with other programs like Solibri issue tracking and MEP modeler.
Also in this release is new support for Revit 2021 and an improved IFC importer/exporter. The model compare function handles structural analysis, modified openings, and custom-defined tags. graphisoft.com/downloads/archicad/updates/archicad-24-update
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PTC paid a remarkable 14.3x multiple for Arena and its cloud-based PLM [project lifecycle management] software: $715 million for a company that made $50 million last year. (A normal multiple is 3x.) The overpriced acquisition came as the result of an optimistic survey indicating that PTC customers have “a 25% increase in readiness for SaaS PLM since the pandemic started.” schnitgercorp.com/2020/12/14/super-quick-ptc-to-acquire-arena-for-saas-plm/
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Here are some of the posts that appeared recently on my WorldCAD Access blog:
You can subscribe to the WorldCAD Access blog’s RSS feed through Feed Burner at feeds.feedburner.com/WorldcadAccess.
Letters to the Editor
In upFront.eZine #1,076 you wrote, "I had found my number somewhere on the Internet." Hello, Ralph! News flash! Just because someone finds something on the Internet doesn't automatically mean that it’s true or accurate! <g> Be careful, stay healthy...
- Bill Fane
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Re: Now is the time to cancel MailChimp
Duff Kurkand wrote in the Release 12 AutoCAD Customization Manual, "Don't overuse icons attempting to encode abstract concepts into cryptic symbols. It doesn't work; ask any archaeologist" (page 98).
When I met Duff (a founder of Autodesk, for those who don't know), he told me he had pretty much single-handedly written all the AutoCAD manuals through at least Release 10. Unlike Bill Fane, I like icons -- well, some of them -- especially when I create them myself so I know what they mean. But, I have found Mail Chimp to be a cryptic experience at best during the many times I've had to use it.
- Steve Wells
The editor replies: Mr Kurkand set the standard for technical publications, and I appreciate him for that. Disappointing, then, that Autodesk subsequently forced only icons on the status bar.
Notable Quotable
“Status is irrelevant. It’s the freedom to make the thing that matters.”
- Jen Gerson
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