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Comment by daedrdev | Hacker News Reader

Blender is a decent option for low effort 3d modeling for 3d printing in my experience

Depends if your goal is artistic or functional. Blender is good if you are trying to make character models, etc. It's not great when you are trying to make a part that has to fit something in the real world and after printing you discover one step half way through needs to be 1mm shorter.

It does take a different set of skills to regular CAD, but I haven't found it that bad for simple 3D printed models that need to be dimensionally accurate.

I have used it to make quite a few functional prints, with the help of making sure my scene units are correct and a CAD plugin.

I haven't tried any of the cad plugins for blender, but I'm not sure how you would retroactively change dimensions in blender. It's usually simple enough to create features to a certain size, but if you need to change them later it becomes significantly difficult.

If I put some holes in something that are 1mm from the edge, but then I print it and see it doesn't line up and needs to be 1.5mm, in Fusion I can just change one number and it all updates. Doing the same thing in blender would likely be very difficult.

thats still pretty easy in blender, just takes a different approach! Goto edit mode in the part, goto vertex mode, wireframe view, select all of the vertexs for the hole on both sides of the solid part, then move then (in the right selection mode) in the proper direction using your keyboard to move the exact amount needed. Depending on the specifics needed, you can setup custom axis and such to move them anywhere needed (lets say you needed the hole .5mm but 45deg from the current one ref'd from a specific edge).

The same thing can be said for resizing whole faces, moving parts, etc... Its all possible and usually pretty easy to do, just takes a different mentality from that of a parametric modeller.

Select the verts, drag them in the right direction. A little pane pops up saying you moved them by .78 mm. Change it to .5mm and you're done.

If you're using boolean operations to make the holes just move the hole-cutter. Same method.

Blender is not a perfect tool for creating 3d prints but it is a capable tool.

You can make a part in a way where you are sure of the tolerance, and you can do the opposite in blender. They have measuring tools and you can be pretty precise.

During COVID I learnt Blender for 3D modelling. It is still my go to.

Many people complain about it being a mesh editor but it works for me. The sheer variety of tooling and flexibility in Blender is insane, and that's before you get to the world of add-ons.

I want to learn Geometry nodes and object generation as I think they will address a lot of the "parametric" crowd concerns. This v5 is meant to be a big step in ease of use of this.

Also, I'm not sure if the different tooling lets me see all the flaws of online "parametric" models, or whether I'm being pedantic. They get frustrating. I have Gordon-Ramsay-screamed "How can you fuck up a circle!".

In MCAD, “parametric” does not mean a high level part or feature is driven by editable parameters or procedurally generated features. Parametric refers to the underlying storage format representing part features in a parametric way rather than as a mesh. Mesh formats like stl cannot represent a circle by its position and radius, while a parametric format like step can. This distinction is more akin to raster (bmp) vs vector (svg) graphics. Both can be generated procedurally by “parameters”, but only with svg can sub-features be faithfully extracted or transformed.

I have some understanding of "parametric" vs "mesh". I looked it up when I saw so many people going on about it.

Maybe it is the export or something. I run the 3D toolbox and often models are not manifold.

I see things like two circles in slightly different positions but both are connected in different ways to the surrounding "single" instance model. Things like this mean you end up with "infinitely small volumes". There is no fully enclosed "volume" and so mathematically there is "nothing to 3D print".

As a model this makes no sense to do, and so it irks me.

But clearly the slicer software doesn't care or autocorrects and people make their 3D print happen just fine.

Sorry, separate point:

>Mesh formats like stl cannot represent a circle by its position and radius, while a parametric format like step can.

This is where I think the Geometry nodes can help. A node (function) can be used to represent the circle with inputs and outputs set or changed as required.[0]

I have not fully explored this space though and so my "hopes and dreams" may well be as useful as thoughts and prayers...

[0] https://docs.blender.org/manual/en/latest/modeling/geometry_...

Alibre has a free option, which does not include sheetmetal bending but otherwise solid software

Alibre does not have a free option. They have a 30 day free trial and the low cost Atom3d package. I bought Atom3d and never use it because it's too painful. If I'm going to endure that much pain I might as well use FreeCAD which at least runs on Linux.

I use Plasticity to model for 3D printing. Having to worry about polygons in Blender is really annoying.

So model using the NURBS tools?

Does Blender have NURBS? I don't even use NURBS in Plasticity, because curves are already essentially vectors. I don't have to worry about polygons at all, and then I choose the tolerances when I export.

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