Types of CAD software...?

Hi all!

I randomly tought about a “field engine” to create 3d shapes, but it’s a raw and immature tought and i’m still… “incubating” it.
The nearer description i can think is something like isosurfacing, but where many fields interact each-other dynamically or simply are static fields that can be edited at each operation by “intersecting” with other fields.
Filletting a corner of a sharp field would be like “applying a filter” (like 2d blur in image editors) or like runing a “field wave” that edit the field while propagate through it (like a 3d diffusion reaction with complex rules).
A “wave” doesn’t need to see the whole shape to work, its parameter will make it load and edit only a portion of the field, and while it moves it applies its effect.
Or a 3d-filter, everything at once, but different parts do not disturb each-other.
No naked/open edges, no crumbling and small surface fragments.
No invalid meshes, no incoerent normals, no popping triangles.
Just a “field”.
Am I talking gibberish? Maybe… it’s 03:00 am here :see_no_evil:


What are the types of 3D design software that exist?
I know some, but my knowledge is scarce as i rarely put my nose outside rhino environment:

  • Nurbs editors, surfaces/curves (rhino)
  • parametric softwares, which often have “solids”… unknown to me what they are deep inside, still nurbs? (inventor)
  • subdivision surface editors (tsplines, SubD, Maya…)
  • mesh editors (meshmixer as simple example)
  • voxel editors (i’ve seen using ZBrush with that…)
  • VR brush/sculpt “games”, which i’ve seen they work with a mix of all the previous. But the usage is so different that they seems another thing.

I guess very often the final result is just a nurbs or a mesh, but what i’m interested in is the engine that is working behind.
Do you guys know anything else? Something “alien” … with a “different paradigm”?

HI Riccardo,…moved toMeta
Might be some info here:

Tsk, no Blender mention.

What about vector displacement? My favourite for that is currently

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Sounds like Monolith to me.

Or OpenVDB (Houdini or Dendro)

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@Michael_Pryor did you mean to share your undergraduate info, along with address and student number with everybody? I don’t really see how this is Monolith?

I edited the link out in case you maybe pasted the wrong one.

I think it depends on how you divide it:

By workflow:

  • Direct Modelling
  • Parametric Modelling
  • Algorithmic Modelling

By geometry:

  • Polygonal
  • Sub-D Polygons
  • Voxel
  • Surface
  • Sub-D Surfaces
  • Solid

By profession:

  • Specialised
    ->Mechanical Design
    ->Product Design
    ->Architectual Design
    ->…

  • Generalized

By Licensing

  • Free
  • Commercial
    ->Floating or not
    ->Subscription

By Pricing

  • Free
  • “Low”
  • “High”
  • Modular

Of course any CAD software fits in multiple categories, but not all are worth to mention. See in Rhino you can create polygonal data, but it doesn’t make it a polygonal modeller. The same is true for Maya’s or Cinema4d’s Nurbs implementation.
The question I would also ask, is a 3d modeller like Blender, Maya or Cinema4d a CAD software? I would rather say no, because its very hard to do engineering-design-related work with these softwares. In my oppinion its rather software to create visual data. But this clearly depends on how people understand the term “Design” in this context. Vector based programs like Adobe Illustrator or Affinity Designer also let you “design”, even are named like this, but nobody would consider this as CAD software…

Sounds like what nTopology is doing with SDFs.

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Thanks for the edit, I dunno what happened there with the links.

I thought of Monolith because of “but where many fields interact each-other dynamically or simply are static fields that can be edited at each operation by “intersecting” with other fields.”

Monolith describes itself like “The volume rendering technique can visualize the voxel image fields without the need for explicitly calculating the isosurfaces, therefore it is much faster than isosurface
rendering and is a preferred method when dealing with complex high resolution voxel images”

Is Monolith not fields of information combined together and materialized by voxels?

I would have cited it as “mesh editor” but that would have been belittle it. I “know” it does much much more, like rhino does with grasshopper. But i think its engine/core is still mesh based… is it? I’m really ignorant.

Cool and interesting! But it feels that is still bounded to the “mesh world”.

You are right and correct.
I was a bit vague with the question.
With “types of CAD software” I wanted to mean to “what type of math/calculations are behind it”.
Not talking about implementation.

Like a metal object can be milled/lathed from a solid block, or obtained from electrical discharge from solid, or cast into a mold, or 3d printed additively, etc etc.

On 3d design softwares is 99% of the times nurbs or meshes … and voxels.

Right.
I lost myself in translation here. I read CAD as simple “computer aided design” but it can also be “drafting”.
I care more about technical software compared of the others less precise but more artistic ones, but my question was directed at “any software that create 3d shapes” (I’ve included VR stuff…).

I still wonder what “Solid” mean in software like inventor.
Is it still nurbs stuff, or it is actually a sort of “math formula” that describes the solid?
The latter would be mind blowing…

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Sounds like you’re thinking of something based on signed distance fields (SDFs) more than voxels.
Because they can be rendered without having to mesh them they can be much faster than explicitly calculating isosurface meshes.
Searching around for that term you’ll see there are some exciting things happening there.
(I’m no expert on this field, just been following developments with some interest for a while)

Inigo Quilez is some kind of wizard with SDFs and he shares lots of great articles and code:
https://www.iquilezles.org/www/index.htm

Matt Keeter:
https://libfive.com/
(This library is actually used inside nTopology - a commercial tool using SDFs)
the paper on the tech here:
https://www.mattkeeter.com/research/mpr/

and some very new work from just the other day on making SDFs from existing objects by using neural networks to find combinations of a few simple periodic fields

and what looks like a really nice minimal API for building and combining SDFs

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Very interesting! I need to learn more about that too!
Thanks!

That monolith really goes very near what i thought of!
Thanks for letting me know that!
I’ll try to keep tabs on that project.

Houdini is indeed “alien” to me, but I remembered talking about it somewhere and they told me it creates FX, but extracting an actual geometry is not the real purpose of that program. Maybe i’m wrong, I need to learn more about it.

Monolith/houdini seems are voxel-based, so there is a “quantized space” where details cannot be smaller.
nTop’s “signed distance functions” can beat that limitation, i guess (?) …
I wonder how the program “find” the “limit surface” of the field…

I’m absolutely not closing this, but already thanks everybody for the answers!
I was hoping exactly this kind of answers, tackling the question from many directions.

It doesn’t, it’s all NURBS surfaces, it just(traditionally)doesn’t let you do anything that leaves your model not-closed. Where that workflow is a hassle is why Rhino exists. It’s an interface paradigm, not different math.

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Thanks for the more examples of SDFs … that thing is frighteningly GREAT!

Someone has already made a C# wrapper for libfive (for in Unity, but it from this it might not be too much work to get it working with Rhino too):

It is definitely not hard to get geometry out of Houdini. It exports a vast amount of geometry types, including solids such as meshes or IGES surfaces. Also, like Dendro it can use volumes which are not quite traditional voxels (which it can be represented by) and they can have a very high resolution because of the way they are computed numerically.

FWIW OpenVDB (Houdini, Dendro) is also making use of SDF’s.

(Screenshot of Houdini Nodes)
Untitled-1

I carried on thinking about some of these ideas and had a play with some SDFs here:
https://discourse.mcneel.com/t/isosurfaces-signed-distance-fields/118745/7

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