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I really want to like FreeCAD but it’s very very easy to screw up things irreparably in the parts designer. For example if you want to cut several faces and the

by qz2 6y ago

I really want to like FreeCAD but it’s very very easy to screw up things irreparably in the parts designer. For example if you want to cut several faces and then realise you have made a mistake on one of the earlier sketches or need to adjust something, the whole model can fall apart. It just disappears. You have to unpick everything you did back to the point you did the original sketch and do it again. This is a shame because the constraint modelling is actually better than F360.

bambax 6y ago
"disappears": there's a kind of weird bug that may be a feature (not sure) where when you undo something, objects don't display anymore. But they're still there. Just select them in the model window and press spacebar and voilà, they're back. In fact the whole tree of your operations is preserved at all times, and you can do modifications at the very beginning of the chain without redoing everything.
- polack 6y ago
  As a total amateur I've run into states where I've been "spacebaring" everything I can but it still wont work. I believe you when you say it's possible to fix it, but for people like me that use FreeCAD to do some 3D models to print once a while it's near impossible to change anything and end up in a working state. If I print a simple electronics case and realize I have to move a hole 1mm in some direction I usually have to rebuild the entire box from the start. When talking to friends they all have the same problem. I want to love FreeCAD, but I usually end up hating it.
  - RogueScientist 6y ago
    In the part design workbench you can create a sketch, you draw a rectangle and you can extrude your box to its precise dimensions with a precise wall thickness. Then you can create a sketch with your features on the surfaces of the part, the sketch features such as holes(circles) connector cut outs can be placed based on a dimensional constraint. Extrude and cut your features. Now you have a 3D box with your holes where you placed them; now need to move a hole change the size of the hole, its as simple as editing the dimension the hole is defined in the sketch, all the other features will update as needed, and you can layer the dependencies forming a feature tree dependency graph. Should take about 10 min to create a pretty complex case enclosure.
    - polack 6y ago
      I agree, it only takes 10 min to make a pretty complex box. But to make it nice you usually need fillets, and then you're better off making the design again then to try to move the hole. Since it goes fast to make a new box it's not a huge issue. Just incredibly annoying.
      - RogueScientist 6y ago
        FreeCAD supports fillets, if your order of operations is set up the fillet will be applied to your features after and it will update the fillet with the changed dimensions, like a parametric cad system should do.
      - jononor 6y ago
        Fillets should always be the last operations. That means when one wants to add more features like holes/pads etc, one should add those to the object before the fillets. Sometimes the fillet operation fails in odd ways though, usually when the number of edges changes. Then one should re-do that last operation, either by removing the Fillets and adding again. Or in 0.18 edit the Edges that the Fillet operation is using in the Property window.
  - bambax 6y ago
    For the record, I'm not pushing FreeCAD in any way, I have no dog in this fight, I'm just a happy user. But moving a hole should really be the easiest thing. A hole is usually a cylinder that has been cut from another shape. Select the cylinder, change its position, done? (No need to make it visible for that).
    - jstanley 6y ago
      You're describing the Part workflow. In Part Design you would move the hole by opening the sketch that defines the circle and changing the position of the circle.
      - polack 6y ago
        Yes, this is how I usually do it and it's not uncommon that it becomes an issue when moving the circle. To be fair there is usually a fillet or something connected to the hole, but I still don't see why that should be a problem.
        jstanley 6y ago
        Moving the circle doesn't usually present a problem. Adding new circles presents a problem because then you get different internal names for the edges and the fillet gets attached to the wrong place. Moving the circle can create a problem if, for example, you specified a 5mm fillet but now the circle is only 3mm from the edge and therefore the fillet doesn't fit.
jononor 6y ago
Getting into an "unsolvable" state is a major painpoint in FreeCAD (and in many other parametric modellers). However you rarely, if ever, need to do everything again. There is usually a way to rebase your features to solve the issue. But how to achieve this requires strong conceptual understanding, and knowledge of some FreeCAD quirks. Map Sketch to Face is a key tool, and knowing that one has to show/select the correct version of the object. For really tricky cases the DAG graphviz visualizer can be useful. Also there are certain design patterns that are less vulnerable to catastrophic model failures. Smart choices of booleans versus feature operations and ordering of these are key to a "robust" design. Having waded through this process quite some times. I should really do a video tutorial on the subject...
- jbay808 6y ago
  > Having waded through this process quite some times. I should really do a video tutorial on the subject... Please do!!
  - stjohnswarts 6y ago
    I second and third it. I've only done simple stuff and had to restart enough that I don't want to try anything complicated and lose days of work so I don't even try.
dekhn 6y ago
Usually you just have to remap sketches. It's awkward, but it works.

by qz2 6y ago

bambax 6y ago

"disappears": there's a kind of weird bug that may be a feature (not sure) where when you undo something, objects don't display anymore. But they're still there. Just select them in the model window and press spacebar and voilà, they're back. In fact the whole tree of your operations is preserved at all times, and you can do modifications at the very beginning of the chain without redoing everything.

polack 6y ago
As a total amateur I've run into states where I've been "spacebaring" everything I can but it still wont work. I believe you when you say it's possible to fix it, but for people like me that use FreeCAD to do some 3D models to print once a while it's near impossible to change anything and end up in a working state. If I print a simple electronics case and realize I have to move a hole 1mm in some direction I usually have to rebuild the entire box from the start. When talking to friends they all have the same problem. I want to love FreeCAD, but I usually end up hating it.
- RogueScientist 6y ago
  In the part design workbench you can create a sketch, you draw a rectangle and you can extrude your box to its precise dimensions with a precise wall thickness. Then you can create a sketch with your features on the surfaces of the part, the sketch features such as holes(circles) connector cut outs can be placed based on a dimensional constraint. Extrude and cut your features. Now you have a 3D box with your holes where you placed them; now need to move a hole change the size of the hole, its as simple as editing the dimension the hole is defined in the sketch, all the other features will update as needed, and you can layer the dependencies forming a feature tree dependency graph. Should take about 10 min to create a pretty complex case enclosure.
  - polack 6y ago
    I agree, it only takes 10 min to make a pretty complex box. But to make it nice you usually need fillets, and then you're better off making the design again then to try to move the hole. Since it goes fast to make a new box it's not a huge issue. Just incredibly annoying.
    - RogueScientist 6y ago
      FreeCAD supports fillets, if your order of operations is set up the fillet will be applied to your features after and it will update the fillet with the changed dimensions, like a parametric cad system should do.
    - jononor 6y ago
      Fillets should always be the last operations. That means when one wants to add more features like holes/pads etc, one should add those to the object before the fillets. Sometimes the fillet operation fails in odd ways though, usually when the number of edges changes. Then one should re-do that last operation, either by removing the Fillets and adding again. Or in 0.18 edit the Edges that the Fillet operation is using in the Property window.
- bambax 6y ago
  For the record, I'm not pushing FreeCAD in any way, I have no dog in this fight, I'm just a happy user. But moving a hole should really be the easiest thing. A hole is usually a cylinder that has been cut from another shape. Select the cylinder, change its position, done? (No need to make it visible for that).
  - jstanley 6y ago
    You're describing the Part workflow. In Part Design you would move the hole by opening the sketch that defines the circle and changing the position of the circle.
    - polack 6y ago
      Yes, this is how I usually do it and it's not uncommon that it becomes an issue when moving the circle. To be fair there is usually a fillet or something connected to the hole, but I still don't see why that should be a problem.
      - jstanley 6y ago
        Moving the circle doesn't usually present a problem. Adding new circles presents a problem because then you get different internal names for the edges and the fillet gets attached to the wrong place. Moving the circle can create a problem if, for example, you specified a 5mm fillet but now the circle is only 3mm from the edge and therefore the fillet doesn't fit.

jononor 6y ago

Getting into an "unsolvable" state is a major painpoint in FreeCAD (and in many other parametric modellers). However you rarely, if ever, need to do everything again. There is usually a way to rebase your features to solve the issue. But how to achieve this requires strong conceptual understanding, and knowledge of some FreeCAD quirks. Map Sketch to Face is a key tool, and knowing that one has to show/select the correct version of the object. For really tricky cases the DAG graphviz visualizer can be useful. Also there are certain design patterns that are less vulnerable to catastrophic model failures. Smart choices of booleans versus feature operations and ordering of these are key to a "robust" design. Having waded through this process quite some times. I should really do a video tutorial on the subject...

jbay808 6y ago
> Having waded through this process quite some times. I should really do a video tutorial on the subject... Please do!!
- stjohnswarts 6y ago
  I second and third it. I've only done simple stuff and had to restart enough that I don't want to try anything complicated and lose days of work so I don't even try.

dekhn 6y ago

Usually you just have to remap sketches. It's awkward, but it works.