This is a project I designed for a sawmill. Not the final draft btw. From this we created every part for Production.Good to hear from another OpenSCAD user! I do use OpenSCAD quite a bit for anything that I will 3d print. Yes, I can design a part in FreeCAD and export the .stl for printing, but somehow I most often find myself turning to OpenSCAD instead.
BUT when it comes to designing a project that includes any machining (or woodworking), OpenSCAD is not the right tool for me. Modelling an assembly is possible in OpenSCAD, but easier and more powerful in FreeCAD ... and producing drawings to use in the shop are not possible at all in OpenSCAD, or at least I don't know any way to do that.
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Polygonal tolerance (loosely stated) is typically defined in settings for different CAD programs. Points in space are straightforward, but curves and arcs are approximated in polygons. In Solidworks, you can get build histories to break if you change the vertex density, because a point on a polygonal circle is always an approximation. I've often seen polygons in F360 3D prints and triangular facets can be seen out of solidworks files as well, depending on how the export was executed. J codes in CAM/CNC are also approximations, as opposed to using boring (lol) tools. STL files degrade some.I do fully understand the issue of tolerances! What I don't understand or have any experience with is how other programs might build the tolerances into the modelling process.
Ahh, I see what you are doing. But I'm thinking this does not add in any dimensions to the drawing, right?This is a project I designed for a sawmill. Not the final draft btw. From this we created every part for Production.
here is the code I use to export 3d to 2d from openscad. it requires you to pick each element to detail if you need and place it into the module area. then export as a dxf. Change the translate offset to suit your scale drawing. Bring into Librecad or your favorite 2d to dimesion and create production drawings.Designed a saw bench system for work. this is the design before final draft. the first rollcase saw motor is from an online resource, the second one i redrew for better use of resources. Acme is needed in the two. Some one may find it useful.www.thingiverse.com
Fairly quick and painless.
//dummy dxf draw
// 1st projection Side
// Second Projection Rear
//Third Projection Top
// Original part
// place your drawing here
You are correct, that I do in LibreCad, both are free and the extra time required is similar to Any other cad program when producing production drawings. So the 3d is a concept drawing(with automation if required) and the dxf is the production or work floor plan drawings with tolerances etc added in.Ahh, I see what you are doing. But I'm thinking this does not add in any dimensions to the drawing, right?
Yes that would be correct in saying that. I don’t find it an issue and it is quite quick to do. The flip side is going from LibreCad to OpenScad. To generate a 150 PFC in OpenScad I do a dxf of its profile then import it into OpenScad with a linear_extrude function. Once you have a library of steel profiles it is very quick and painless. Apprentices like it because it’s free and they can use it on there home computers. Last Autocad HP computer I bought was over $7000 to run Inventor and Autocad.Understood. I see how this could work well. The one thing I'm thinking might not be possible without extra work would be showing hidden lines?
I use the QCad community version, so still free and with no worries about it suddenly being terminated like DraftSight (which was very good).
Statistical tolerancing is covered in ASME 14.5. You typically want the most difficult part (cost, manufacturability) in a stack of tolerances to have the widest tolerance. The formulas are in basic algebra. There's a lot of snake oil sold in CAD programs too with CFD and fatigue analysis, but I could see something like that for electrical loads being very handy.I can see an analogy to mechanical designs by specifying a tolerance in a diameter, length or something and using Monte Carlo to determine clearances between parts as those dimensions varied.
I have noticed that quite a few CAD programs include CFD and finite analysis. I would agree with you about snake oil as often they are a bit shy on the code origins. The lack of snake oil is one the features I like about FreeCad. It has a workbench for linking into OpenFoam, a very powerful opensource CFD package. The two programs complement each other as OpenFoam has no graphical front end, so my aim is model generation in FreeCad and use its CFD workbench to then feed in the boundary conditions to OpenFoam and run the solver. I should add that my interest is strictly home research. Being retired does not even allow thinking about propriety packages. Though I should say that even if I was still in the game OpenFoam would be very attractive as it is proving itself as good if not better than Fluent now.Statistical tolerancing is covered in ASME 14.5. You typically want the most difficult part (cost, manufacturability) in a stack of tolerances to have the widest tolerance. The formulas are in basic algebra. There's a lot of snake oil sold in CAD programs too with CFD and fatigue analysis, but I could see something like that for electrical loads being very handy.
Thankfully none of these tools are all that necessary for home CAD use. Phew!
Blender is pretty amazing. Some people use it for meshing their OpenFoam models. I don't think I have the time to really get into Blender as well. It is a big subject in its own right.I was looking at OpenFoam + Blender and it looks pretty amazing. Looks like a deep rabbit hole.