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That's awesome. I've futzed around with OpenSCAD a bit, and the OP is talking about a workflow similar to what I had in mind for my projects. What's neat is t

by ansible 12y ago

That's awesome. I've futzed around with OpenSCAD a bit, and the OP is talking about a workflow similar to what I had in mind for my projects. What's neat is that you can generate a set of parts once (in code). You then assemble those parts (functions, really) into 3D shapes for visualization. And you lay out those same parts in a plane for 2D fabrication. The main difficulty I had was that it seems to be necessary to calculate everything. As a simple example, suppose I've got a triangle-shaped part, and stick the flat side of it on a square part. What's the distance from the tip of triangle to the opposite flat side of the square? OpenSCAD knows, in some sense, because it drew it. But inside my OpenSCAD script, I don't, and I have to calculate the geometry in my code. If there was some way to specify and capture the position of that point (or whatever), then it would be much easier to connect parts together.

anjowo 12y ago
That is one of the difficulties. In a few of the more difficult calculations, I did what I could on the python side of things, and emitted a statement or function in the generated openscad files.
bhouston 12y ago
> If there was some way to specify and capture the position of that point (or whatever), then it would be much easier to connect parts together. This is usually done by a constraint solver. The most popular one in the industry is D-Cubed 3D DCM by Seimens: http://www.plm.automation.siemens.com/en_us/products/open/d-cubed/products/3ddcm/ http://www.plm.automation.siemens.com/en_us/products/open/d-... I do not know any open source equivalents for 3D constraint solving. There is a few 2D ones that are open source I understand.
- sedachv 12y ago
  https://github.com/genworks/gendl https://github.com/genworks/gendl does this by having you describe parts and sub-assemblies as objects, and then generating geometry commands from the object graph.
ltta 12y ago
I tried to get into various CAD applications at various points in time and never managed to "get it". It was mostly about the interface, you just have to invest a lot of time (more than I was willing to spend) to get even remotely useful results. OpenSCAD on the other hand immediately clicked - at least for me as a programmer. I just had to look up the available primitives and combine them to my liking. This totally jibes with my mental model of the thing I want to build and parametrizing your models is pretty easy. My main gripe with OpenSCAD is that it is missing good features to generate more "organic" shapes, i.e. beveled edges and rounded corners require a lot of work. They are possible (i.e. with Minkowski sums) but the resulting complex shapes quickly bring the engine to its knees.

by ansible 12y ago

anjowo 12y ago

That is one of the difficulties. In a few of the more difficult calculations, I did what I could on the python side of things, and emitted a statement or function in the generated openscad files.

bhouston 12y ago

> If there was some way to specify and capture the position of that point (or whatever), then it would be much easier to connect parts together. This is usually done by a constraint solver. The most popular one in the industry is D-Cubed 3D DCM by Seimens: http://www.plm.automation.siemens.com/en_us/products/open/d-cubed/products/3ddcm/ http://www.plm.automation.siemens.com/en_us/products/open/d-... I do not know any open source equivalents for 3D constraint solving. There is a few 2D ones that are open source I understand.

sedachv 12y ago
https://github.com/genworks/gendl https://github.com/genworks/gendl does this by having you describe parts and sub-assemblies as objects, and then generating geometry commands from the object graph.

ltta 12y ago

I tried to get into various CAD applications at various points in time and never managed to "get it". It was mostly about the interface, you just have to invest a lot of time (more than I was willing to spend) to get even remotely useful results. OpenSCAD on the other hand immediately clicked - at least for me as a programmer. I just had to look up the available primitives and combine them to my liking. This totally jibes with my mental model of the thing I want to build and parametrizing your models is pretty easy. My main gripe with OpenSCAD is that it is missing good features to generate more "organic" shapes, i.e. beveled edges and rounded corners require a lot of work. They are possible (i.e. with Minkowski sums) but the resulting complex shapes quickly bring the engine to its knees.