3/19/2023 0 Comments Deltacad student![]() The user now needs to tell FreeCAD where the new "magenta" edge is (and often redefine some constrains in the sketch). In FreeCAD, this typically results to a situation when the magenta edge cannot be properly located and the Pocket faills (since the circle defining the hole is positioned relatively to the magenta edge). This adds 2 vertices, 3 edges, and 1 face to the solid which is the source of the second operation Pocket (which "drills the hole"). Lets say the original cuboid creation (Pad) would be modified so that its vertical edge A is chamfered.Now the problems start when some new edges appear in the new version or some edges disappear from the new version of the object on which a operation is based: I suppose this will work the same way with all commercial CADs. dimensions changed, position of some features on the object changed but number of vertices/edges/faces did not change and they are all connected the same way). If the magenta edge changes so does the position of the hole.įreeCAD can typically redo all your operations without any input from user if the new version of the object they operate on and the old version of the object are perfectly isomorphic (e.g. Notice that the pocket location is constrained to the position of the magenta edge of the cuboid. The 1st was extrusion of a rectangle (Pad) and the second one was creation of a circular hole in it (Pocket). Notice the cuboid on the picture (a screen shot from FreeCAD). I have a few questions for real CAD users. When a historical parameter is changed and the change leads to changes in number of faces/edges then the later steps typically fail and you need to redo them. I guess I should update :-/Īre commercial CADs parametric enough? When you change some parameters in some historical operation will it rebuild all the later steps correctly? Will it rebuild them correctly even when the historical parameter change leads to a solid with different number of faces/edges? This seems to be a problem in FreeCAD. Please, notice that I use git version 0.r3069.ga7d297c-1 (from ) a newer version may behave much better. Things I miss most in Part/PartDesign workbenches is snapping. But then you loose parametric behaviour when changing some parameters in history. You can always make things better by copy/paste the last model (without history) into a new FreeCAD document. Here is an example of FreeCAD model which starts to be big with history (when its history is kept the file has 32MiB and is saving for about 10 seconds): When the history is kept then also not so big models can look big. It is not such a problem of the model itself as the fact that also the whole history how the model was built is kept. (I guess this is a common feature of big CADs.) It is good to save a lot (especially before deletions or changes in history) but saving gets really slow with bigger models. The way/history how your model was built is stored so if you need to modify some parameters in previous steps there is good chance you can change it in history and the later steps will rebuild appropriately. Some of the FreeCAD bugs/limitations are actually OpenCasCade bugs/limitations. If you know python you can work around the bugs (or detect that something is wrong) from the "python console". It is somewhat buggy so it can be hard to use if you do not know python. Here is an example of an OpenSCAD model which just starts to be more complicated:įreeCAD looks more like a real CAD. CGAL path will be ok with bigger models, but you cannot "debug" with it easily. The internal path gets very slow for more complicated models (about 5000 triangles, which corresponds to about 400 lines of OpenSCAD script). One is internal (debug) and the other is CGAL. It is good for simple things which need to be highlly parametric. You write a script which builds your part. OpenSCAD is more like a scripting language.
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