Plasticity: CAD for Artists
plasticity.xyz
plasticity.xyz
Parasolid, the library used to perform the geometric operations (the most difficult and important part of a CAD program) also powers the likes of SolidWorks (the industry standard), NX, and Onshape, and is arguably the best in the world. Its licensing cost is presumably a large part of the Plasticity price.
At least for consumer stuff where you anyway eventually just want triangles for either rendering or 3d printing.
If your industrial workflow includes CNC machines you may benefit from actual analytic surface cuts and unions - maybe.
Parametric modelling is similar to 2D vector graphics formats in that instead of defining where vertices are placed in a coordinate space, it builds the model based on an instruction set that includes primitive shapes like circles but can also include complex curves defined using splines (NURBS)[0].
Constraint solving is a way of mathematically deriving the possible shapes an object can take based on the geometric constraints applied to it. For example, a 2D equilateral triangle could be defined by setting the length of one edge and then constraining all edges to be of equal length. The coordinates of the vertices are derived from these constraints.
SolveSpace [1] is an open source parametric modeler with a constraint-based solver that you can explore if this is something you're interested in.
[0] https://en.wikipedia.org/wiki/Non-uniform_rational_B-spline [1] https://solvespace.com/index.pl
It’s been a white since I used it, though. I use CAD pretty infrequently these days, though, and generally just let the mechanical engineers do it (or maybe do it myself in FreeCAD).
> The kernel market currently is dominated by Parasolid and ACIS, which were introduced in the late 1980s.
> Autodesk ShapeManager is a 3D geometric modeling kernel used by Autodesk Inventor and other Autodesk products that is developed inside the company. It was originally forked from ACIS 7.0 in November 2001,
... so it's quite like OS kernels. There's WinNT, AT&T UNIX, couple advanced forks of UNIX, and GNU/Hurd.
1: very broadly speaking, to me it could take rest of my life
Perhaps coincidentally the rule of thumb is that it takes about 100 developer-years to go from zero to a viable kernel.
Of course my trial version is nowhere near there, but watching several videos it appears that even the highest settings still are far from a proper high-poly export.
Since I work with 3D prints, that is a blocking issue for me, BUT the videos are all several months old.
Anyone with a more recent experience with Plasticity has something fresher information about that?
> Are there parametric features? eg. Can I say "this line is 35mm long"?
> I want to emphasize to everyone that this is for concept artists. It’s nurbs used to create interesting shapes and fillets. While there are some parametric features, they’re completely de emphasized compared to something like fusion or solidworks
However there are no parametric controls for the elements of your shapes or drawings. Keeping these constraints out of mind certainly helps me get into a flow when modeling, much more akin to subd or poly modeling while maintaining the benefits of NURBS. But for adapting models quickly for more flexible designs isn't /really/ the tool for it. You can take it pretty far though!
I personally use Plasticity to model all kinds of things including 3d-printed items (vacuum wall mounting, iPhone lens mount, storage cases, clips...) All of these items needed to be measured accurately and Plastiticy was able to handle that without issue.
I've been using 3d software for 20+ years, Max, Maya, Blender, XSI, Houdini, Wings3d, Lightwave, Modo, ZBrush, Mudbox... "lots" of 3d software. Some get the job done and some are even a pleasure to use, Plasticity decidedly in my mind does both.
It's a lot like Blender, if Blender was a few degrees more usable for CAD. That said, I've yet to try the Blender CAD Sketcher addon (https://www.cadsketcher.com/).
I've been meaning to look for a Fusion360 alternative that can run on linux and doesn't cost $$$$/yr.
It's still weird. That's for sure. But very much usable as a fusion360 replacement for simple to intermediate 3D printing work.
If it looked like FreeCAD was trying to improve the UI I think I'd be throwing some money their way to fund it. But it appears they're happy with the way it works, as these paper cuts have actually gotten worse over time.
It's just FreeCAD, not FOSS-CAD-as-a-whole. Kicad gets better and easier to use each release and I am well aware what a gift it is to engineering work.
but last time I tried it I couldn't figure out how to do almost anything. Fusion 360 and solidworks (and I think onshape) all just "made sense". Throw down a sketch, extrude some surfaces, etc. FreeCAD was a struggle for me and I went back to fusion 360 mostly because I was already familiar with it.
I don’t pay for my Fusion 360.
I've ended up preferring to use cadquery instead, since copilot makes iterating designs with it pretty easy. But it looks like Plasticity might have the kind of workflow I'd like.
CAD supports true curved surfaces. A sphere in CAD is a genuine sphere, and you can decide how accurately to render it independently of your modeling operations. CSG is a core technique in CAD modelling, with no special tricks needed to get good results.
To me, the CAD approach is more intuitive, but it's true that vertex modelling can be very fast when you don't need high precision, so I can see why artists like it.
I've lost count how many Fusion360 modelers I've seen that can't properly turn their models into a mesh and 3D print curved surfaces with visible polygon banding lol.
> vertex modelling can be very fast when you don't need high precision, so I can see why artists like it
It's not about speed, it's about control. When making assets for rendering all kinds of wild tricks are sometimes needed that go beyond modelling solid objects, plus adjusting UV coordinates for texturing and the like.
Of course for artists, accuracy probably doesn't matter.
Let’s say you have a hole in a part and you need it to be a certain distance from an edge.
The rookie way is to pull out your calipers and actually measure that distance and put it into the design.
But let’s say you know the hole needs to be co-tangent to an invisible line between two other points. In a parametric modeling program, you would say it as it is: this hole is co-tangent to this invisible line which is defined by these two points.
…which gives you a HUGE advantage: let’s say you have to move one of the defining points… well because you defined it parametrically, the hole would just magically resize and reorient itself instantly. And let’s say you extended the hole parametrically to another surface… well that would update too.
But if you did it the rookie way, you would have to pull out your calipers and re-measure everything. Risky risky too. Have to double check all your measurements all over again.
In Blender, because shapes are not actually mathematical shapes, you aren’t going to be able to define co-tangents or constraints or derive any measurements.
That’s why, no matter whether you are a hobbyist or a large professional engineering firm, you might much prefer parametric design because it saves you so much time when drawing out or changing the part. It has nothing to do with the precision of your calipers or the precision of your final product.
(That said, not all tasks are fit for parametric design. I wouldn’t design a game model or rendered scene with parametric design. I would use Blender. Also to be said, I know there have been attempts to add parametric design to Blender but I’m not familiar with how far they are.)
It's Illustrator and Photoshop difference, Ai is superior to Ps if you're having to select and move individual brush strokes all the time. Otherwise it's near polar opposite of course.