This is a simple example to illustrate assembling a model from multiple parts as opposed to using a boolean operation between parts, csg methodology, to make a hollow cube.
But when making something from timber screwed together, or plate welded, then I prefer to make every real world part a separate solid, sometimes a solid would require some csg (I mean here boolean like "cube - a cylinder" to make a "bolt hole" or whatever). The idea I had was that when finished my model by default contains all the exact details required to manufacture the item and its components. I use groups as well as the part history to keep it all organised, my project is in effect a bunch of sub models, so they can be logically extracted for the manufacturing and supplier drawings etc.. In a way my model is like a bill of materials, to some extent.
In short when my project model is finished in FreeCAD, it is pretty much ready for manufacture.
Modeling the cube from individual cubes also allows me to think about and define what I am going to do at the component intersections.
The future functionality of FreeCAD with "definable variables" and the "assembly work bench" will also be useful in this sort of case. As you can see if I change some aspect of a part of the model/project, e.g. the thickness of one of the steel plates used, then I have to manually change the dimensions and/or positions of the other components in the model/project. For the moment I am using my brain as a substitute for the assembly work bench / 3d solver!!!
In this "cube from welded plate" example (model attached), assuming that one ordered the "front plate - blank" from the metal merchant and made the cutout in one's own factory, then "front plate - blank" could be extracted from the model for sending to the metal merchant, and the "front plate with cutout" could be extracted for the factory workers on the factory floor so they know where to cut out the hole.
If I had made the cube by "difference boolean" between a larger and smaller cube, then the corners would not be defined, and I would have no component drawings. I actually made this mistake on one of my first designs. I made a closed cube early in the model but was stuck a bit later when I wanted to make one side plate only partly opaque, so that I could see the components I wanted to weld to the inside off the wall of the cube. With the "boolean" construction method I had a cube where I could only easily adjust the opacity of the "whole cube", so that then meant I couldn't see the inside of the opposite wall that I wanted to weld the bits to.
The FreeCAD file attached "cube from welded plate.fcstd.zippednotreally.zip" is not zipped, to open just delete ".zippednotreally.zip" from the file name and open in FreeCAD.
- cube from welded plate with 4 different corners.jpeg (127.1 KiB) Viewed 4973 times
