• luddybuddy [comrade/them]@hexbear.net
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    29 days ago

    Prints have a design language to them which allows you to express fully constrained geometric designs on a napkin if you need to. Dimensions, radii, diameters, angles, datums, positions, projections, sections, GD&T. None of this is obvious in a 3D model. You don’t know what the driving dimensions are, what can be inferred from other dimensions, if it is a coincidence or a requirement that two features line up, etc.

    This is so critical. In architecture and structural engineering, you can add to this that you don’t actually know a lot of the real dimensions - you’re laying out the important ones from the structural grid or from survey points, and whatever is left doesn’t matter.

    Even markup, at least in a design environment, can be done in 3D (or at least on a computer), but the communication of constraints, that is, what dimensions are important and which are irrelevant or unknowable has not yet been developed in 3D models, and I suspect it will be some time before any useful language for that purpose stabilizes.

    • PorkrollPosadist [he/him, they/them]@hexbear.net
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      29 days ago

      Even markup, at least in a design environment, can be done in 3D (or at least on a computer), but the communication of constraints, that is, what dimensions are important and which are irrelevant or unknowable has not yet been developed in 3D models, and I suspect it will be some time before any useful language for that purpose stabilizes.

      This is a thing which exists in a lot of CAD packages, and it is reasonable for an engineering firm and a contractor to use the same CAD package as part of a contract. Some of the more fancy (expensive) stuff can even check for interference in assemblies throughout tolerance ranges. But still, if you cannot turn your design into an ASME / ISO drawing I have severe doubts in your competence.

      • luddybuddy [comrade/them]@hexbear.net
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        29 days ago

        Yeah, I know some of that exists; it never showed up in my world. We never modeled buildings with enough detail to make it really useful. Occasionally someone would get excited about Tekla and we’d spend some time trying to do shop drawing reviews in 3D and then go back to PDF. What I meant was that it isn’t yet a standard thing that is understood by any technician in the industry, it’s proprietary software that is subject to change with every release.

      • Runcible [none/use name]@hexbear.net
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        29 days ago

        I’m fairly sure some things(like impeller or fan blade geometry) can’t be meaningfully communicated on a drawing and only through a model. I expect some of that to be more common as AM allows manufacture of internal features designed for/around fluid flow.