Mon Oct 23, 2017
Recent FreeCAD learnings: To edit the PC frame I used pockets to cut the unwanted section, then pad a little rectangle to complete the frame, finally I created simple copies (in Part menu) and assembled them.
Recently I've been working with clones (Draft wb) and I liked them, as they change when the cloned object changes, so it's easier to edit.
Also, in the tensioner, I found out that constraints work fine with fused objects, I mean, we can expand the fusion and edit the fused objects, then use the Rubik's cube tool in Assembly2 wb, and the fusion will update the objects placement... very nice.
(Moved from Jose's Log)
Hey, Roberto, this is Emmanouil. Thats way I am pushing the constraint assemblies. Check the part library on the Power cube to see what I mean, I put the frame/tank already.Each one should make changes to one plate of a module. And then later a cad file that has ONLY imported parts is made. That makes the dxf export easier also, part list easier. We have to learn to break down the parts in Freecad in order to work efficiently Jose sorry for getting in the way! :) :)
- I'd like to test your idea, could you share the repository?
- Also, according to that workflow, where are we supposed to make the changes, in the constrained Frame module or in the separated Frame parts?(Roberto)
Roberto, I have not any repository, but I will show you the files in wiki so to make it clear to you. Hopefully the github will be the way to go, because that continuous reuploading in the wiki is not ideal.
So, the idea is that the metal parts that will need to be isolated anyway and being put in the parts libray or have to be CNC cut, have to be designed in unique files. So for example if you see the Power_Cube_v17.08 at the parts library section you can see the parts that are used to assemble the Frame module. So the work load is distributed. Then one new file with NO other parts made, just the part imported by the "Assembly2/Import" (be aware this is different than the File/Import") is made and saved as the module. The imported parts could be constrained, but it is not mandatory, even though is strongly advised. By constrain everything, in a later minor change(lets say we change the dimensions of the plate) the parts will go automtically in place, saving huge time! The other HUGE advantage (this one of the reasons we CAD anyway) is that the Assembly2 workbench can calculate any overlaps. This feauture is important when we use that poka yuke (or whatever they are called) cuts!
In bigger machines,like the CEB, extra time is saved because some modules are repeated in the desing. (like legs, rod holders, attaching squares etc). In the CEB press I used another extra level of assembly. Individual parts and/or modules where combined to make sub-assemblies. And these sub-assemblies (7-8 of them if i recall correct) are making the final cad. So the developers have a choice of how much detail the want to use on AIL/EPA, and they have much, much more clear tree structure in the design cad itself.
Open the http://opensourceecology.org/wiki/File:PC_1708_Frame_module.fcstd to take an idea. Once you get it , open the http://opensourceecology.org/wiki/File:CEB_17.08_CAD_Assembly.fcstd to see the bigger machine.
One minor drawback is that if you try to update the individual parts, you have to download them, and update the path. Freecad does it for you if the file is at the same directory as the master cad file. Anyway, that will get improved at some point by using "relative" paths" instead of hard links. But anyway don't mind that for now. See the structure and tell me what you think.
I believe that is it a very strong tool that we are not utilizing yet. People where frustrated by the extremely poor documentation on the Assembly2 workbench, but I mastered it now. It has only a few bugs IF you know how it works. Also -when-explained- it will make it easier for new developers, as the axes/orientation in the Freecad is too complicated for newbies. With the contraints you only click on the planes, and the items attach automatically, no need to move items through the axes' numerical values any more
- Emmanuoil, this: File:LFW tensionerswitch.fcstd is my first test of your workflow. I think It's an amazing result, specially for the ability to edit the assembled parts. I experienced one bug when FreeCAD closed unexpectedly after a constraints conflict. So it's important to save the work often. Tomorrow I'll test it in a Master Assembly. (Roberto)
Great job! Now -my apologies if you already saw these- take a look at a few useful features: a)The menu that shows up only when you have the Assembly2 workbench enabled. Right click on a constraint. You have some options (Animate,REdefine,Select Object and Select Elements) Very useful all of them. Be aware that the Animate is there not for animation, but to show you if you have any Degrees Of Freedom (DOF). b)The offset property, and the Direction of Contraint property c)The "Check Assembly for Ovelap/interferance" You can see that you have some overlap. Can you see how useful is this on a big machine with complicated cuts? We can see the conflicts right away. d)The Animate Degrees of Freedom (you have 2 DOF left :) These are the rotation on the bolts. Not significant, but get used to set it to "True" as when there are lots of circular constraints it will make it difficult to see the real unconstrainted object between these. So keep the DOF dialog empty. e) You can drag the items around. No worries. Press the "Rubik's cube" (Solve Assembly 2 constraints), and everything will go back into position. f)if you add a drawing-dimensioning page, you can have the part list right there :) (Emmanouil)
- WOW, I hadn't realized all those features. I did an experiment -I think you already noted this- I created a muxedAssembly and hid all the single parts. Then imported the file into a new one, as if it were a Master Assembly. Then I edited the imported muxedAssembly, and edited again one of the hidden parts. After saving and updating the changes when required, I found I was able to modify a single part even in the Master Assembly, without moving or replacing anything. Just beautiful.
I haven't ever touched the muxedAssembly!!!! :) :) I will experiment with it later!! So, what, can you edit each individual part on the assembly???
- Yes, I'm going to do a video to show what I did.
Roberto when you pressed the Spape 2D view, the circle looked like an octagon. Can you double check it is a circle?
for some reason I have done none of these steps, and my direct File/Export/Save as autodesk dxf works fine. Can you tell me what was the problem that you are having and the direct export does not work for you guys?
- Yes, I wondered the same about the circle, but when it is exported as DXF it looks correct. Even bringing the circle to a wire (after downgrading the object in Draft Workbench) which looks much better than the Shape2Dview object before exporting, after exporting the circles look identical in the DXF files. You can see our problem looking at the 2 versions of this file: File:CEB Press Drawer Side.dxf. Maybe it's about the FreeCAD version, I read that DXF is better supported on 0.17. But I prefer 0.16 for now. Roberto.