Comment by Klaus23

Comment by Klaus23 7 hours ago

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Blender is great, but it still can't replace a CAD program. I tried using it for simple CAD tasks (before geometry nodes were released), but the experience was so poor that I quickly switched to FreeCAD. It was worth it, even though it took some time to learn how to use the new program.

FreeCAD is pretty buggy, confusing, and sometimes limited, but its workflow can't really be replicated with Blender. Once you have worked with a CAD program for a while, you realise that certain things that are almost impossible or annoyingly difficult in Blender can actually be pretty easy.

It would be great if the two programs could be merged. Blender could benefit from better CAD functions, and FreeCAD could benefit from everything else Blender provides.

rcarmo 6 hours ago

The CAD Sketcher add-on goes a long way towards making it more usable. I’ve been hacking away at it myself (should go back to finish what I was adding…).

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  • Klaus23 4 hours ago

    Nice. That wasn't on my radar. I was already happy when Blender made significant progress in parametric modelling with geometry nodes. Together with CAD Sketcher, it looks pretty usable for modelling. I hope the whole thing improves quickly, but I suspect they have a long way to go before Blender can be considered a proper CAD program.

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elcomet 7 hours ago

Can you explain more? Which things are impossible in blender

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  • argomo 6 hours ago

    Spiritually, Blender is to FreeCAD what Gimp is to Inkscape or what BMP is to SVG. With Blender you're massaging piles of anonymous polygons so they look right aestheticallY, while with CAD you're composing geometric primitives to make a precise blueprint for a 3D object that just happens to be rendered with polygons. The former is better for art while the latter is better for manufacturing.

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    • koolala 6 hours ago

      Any there any open CAD file formats that lay a foundation for describing this kind of 3D data without classic triangles?

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      • gf000 22 minutes ago

        Parent's comparison is pretty great, but it shouldn't be "overdone". It's not really the format that's different/a problem (it's not hard to make a blender object from a CAD design - the same way an SVG can be rendered to PNG, and similarly irreversible in both cases), it's the whole design flow.

        CAD uses geometry primitives with parameters and exact sizing (e.g. you draw a rectangle of this size, and cut a whole into it this and this offset from one of the corners, and you expand this shape to 3D). As mentioned this can be approximated via geometry nodes, but they are very different in "ideology".

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      • Klaus23 4 hours ago

        A .step or .stp file encodes the model as mathematical shapes, rather than approximating it with polygons, but it doesn't save the entire parametric workflow or history, only the final result. As far as I know, there is no widely adopted file format that also saves this information.

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  • mamonoleechi 5 hours ago

    CAD modeller are good at producing parametric 3d models. You can make use of spreadsheets and constraints to create a piece, that will later super easily be changed.

    https://en.wikipedia.org/wiki/Constraint_(computer-aided_des...

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    • diggan an hour ago

      > CAD modeller are good at producing parametric 3d models

      If that's the only thing they do better than Blender, then it sounds like their days are numbered. Has to be more benefits right? Blender exposes a pretty wide Python API, loading spreadsheets ends up pretty simple, and together with Geometry Nodes, you can even visualize it in a way that makes somewhat sense. Constraints been existing for a long time in Blender too.

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  • timonoko 6 hours ago

    If you try OpenScad-style adding and subtracting volumes, the syntax is pretty horrific. It is impossible to script objects that way. Quote Gemini:

      However, implementing a full OpenSCAD-like syntax and robust CSG system from   scratch in Blender Python is complex due to Blender's mesh-based nature versus OpenSCAD's mathematical description. Blender's boolean operations on complex meshes can sometimes lead to topological errors.
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    • jacquesm 6 hours ago

      To be fair though, OpenSCAD works best too if you do this during the generative step and not after the fact. I've used it to remix existing STLs so it definitely does work but you really have to watch the areas where two shapes get close to each other, especially if there is a lot of fine detail.

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