[HN Gopher] Constraint-based geometry (CAD) sketcher for Blender ___________________________________________________________________ Constraint-based geometry (CAD) sketcher for Blender Author : khimaros Score : 64 points Date : 2022-05-22 17:17 UTC (5 hours ago) (HTM) web link (github.com) (TXT) w3m dump (github.com) | pen2l wrote: | This a pretty interesting development. | | I'm wondering to what degree tessellation is configurable, e.g. | if I want polygon-dense output to have nice curvatures for | additive manufacturing, or polygon-light output for rapid | workflow and speed if I have complicated geometry. | cultofmetatron wrote: | I really wish there was a open source cad modeler on the same | level as blender. It really is next level. My dream for if my | startup succeeds is to bootstrap such a product. Especially if it | had a fully extensible architecture. it would be possible for | third party services to plug into it (both paid and open source) | for creating and designing new inventions. | NonNefarious wrote: | Same. I don't know much about 3-D modeling, but I took a Maya | class years ago and was annoyed at design flaws in its UI. | | I didn't expect much from Blender, owing to the shitty UI | offered by other widely-used open-source software like GIMP and | Audacity. But I was pleasantly surprised by Blender, and I'm | excited to learn it. | | But the CAD space is dominated by pay-only rental-style | solutions, and even most of those seem to be Web-based | (Autodesk) or Windows-only (SolidWorks). | dapids wrote: | Is blender not open-source? | cultofmetatron wrote: | blender is a mesh modeler, That means the underlying | represntation of the scene is a a set of surfaces connected | by nodes subdivided by triangles. Its efficient and quick for | 3d animation and concept art but not so great for cad design. | | real cad tools like fusion360, autocad etc are parametric. | they represent a shape in the form of constraints. The | underlying representation of the shape is different in a way | that facilitates modeling something that you are going to | create a real world counterpart from. | | Yes there are open source cad programs but nothing I've seen | comes close to rivaling professional tools the way blender | does. | NonNefarious wrote: | Yeah, thanks for that explanation of the issue. | dapids wrote: | Thanks for the insight. | throw_m239339 wrote: | Blender is mostly an artistic tool (mesh modelling), which | actual CAD software is designed for industrial engineering, | accurate physical simulations, manufacturing, and | architecture (constraint based modelling). | Animats wrote: | Yes. Blender has some volumetric operations. You can take | the union or intersection of two meshes, or use one to cut | out part of another. But it's a bolt-on to an underlying | mesh system, and the resulting meshes have lots of ill- | chosen triangles. | | Serious modern parametric CAD (Autodesk Inventor, | Solidworks, etc.) does constructive solid geometry well, | but is not well suited to animation. Making a face via CSG | is terrible. Although it's gotten better; you can now do | sculpted shapes in CAD, because people design cars in them. | That has both sides of the hard problem - the smooth shapes | must look good, and the bolt holes for the stamping dies | must line up precisely. | rurban wrote: | solvespace is much better than blender in modelling. | Piezoid wrote: | This add-on is using solvespace for solving constraints. | throw_m239339 wrote: | FreeCAD? It is used professionally by a lot of big companies | such as Behringer to design hardware. | | https://www.freecadweb.org/ | slabity wrote: | I use FreeCAD relatively often (once or twice a month) over | the past 3 years and I can say with certainty that it is | nowhere close to Blender in terms of quality or stability. | | I've been keeping up with the latest versions, but even with | all the bug fixes that go in I am more likely than not to | have it segfault or lose its GL context or something else | that causes it to crash. This isn't even hyperbole, I | literally get 2 or 3 crashes at minimum per session, and when | it happens it's rarely reproducible. I simply save after | every couple of changes I make because I've just come to | expect it to happen. | | When it does work, I frequently run into problems like the | infamous topological-naming-issue that, while I understand it | is a difficult software problem to fix, I do not run into in | the other CAD programs I've used. The only way to avoid these | kinds of issues is to understand the underlying cause and | then adjust your workflow so that you don't run into them. | | The only reason I use it is because there's not really any | other FOSS that fits the same niches. I did learn about | SolveSpace and this blender plugin today though, so I'll | probably take a look. | samwillis wrote: | The fundamental problem is that there isn't a good enough open | source parametric kernel. FreeCAD uses OpenCascade which is the | best available, but quite dated, FreeCAD is pushing it to its | limits. | alhirzel wrote: | Is there a good description of what such a parametric kernel | does? Or are there any alternatives to OpenCascade? ___________________________________________________________________ (page generated 2022-05-22 23:00 UTC)