Stuck on FreeCAD - Please help

Hello! I am trying to recreate a volume knob and I am having an issue making the stabilizing walls and just can’t figure out what to do. I honestly don’t know if I’ve done any of this correctly. I will attach photos and the FCStd file.
Any help will be greatly appreciated!

knob.FCStd (39.8 KB)



Just looked into your FreeCAD file. It seems you made your life harder than necessary.

First of all: Use the RealThunder version of FreeCAD. It will make your live alot easier.

Since your model is just extruding in one direction (from the table up) you can use a master sketch for that.

You basically draw all lines into one sketch. Of course you cannot extrude the sketch as it is, but you can select the parts you want and do different extrusions with multiple pad or pocket operations using the same sketch with just different lines selected.

I did that in my first example. You can load the file into the official FreeCAD and it will show everything, but creating such a model is way harder. The RealThunder version also has far less bugs.

However. I added a file containing two approaches to solve your problem. To make my live easier I used a spreadsheet to store all measurements as this is the way to go anyway. It may look like useless work, but it makes reusing values so much easier and in the end you can modify your part by just changing the values in the spreadsheet.

The second example is a more vanilla approach using multiple sketches and doing basically the same as you did. However I prefer adding material only if possible. So I created a bottom, a ring and the center connector. So no pockets in my solution.

After drawing and constraining the connector shape, I added a blue helper circle using the inner diameter measurement (hurray for the spreadsheet). I drew the horizontal/vertical lines for the plus shaped stabilizers and connected them to the blue circle and the connector shape. I made them symmetric to the x and y axis and defined a fixed spacing using blue lines. Last step was creating four arcs between the lines at the outer sections of the stabilizers.

Once the lines are constrained, you can use the trim tool to remove the inner lines. Since everything is constrained it just opens it up and you have a shape that can be extruded. The flat side of the connector is tricky. After cutting the middle sections the sketch is suddenly no longer fully constrained. This is because the top and bottom lines are no longer vertical. After readding the original fully constrained shape returns.

I hope it helps. If you have questions, just ask. CAD allows you to do stuff in multiple ways. just use the one that suits your :smiley:

knob2.FCStd (113 KB)

This is so cool! Thank you so much!

@Geit Outstanding advice about using FreeCAD. Thanks for sharing it. I have not made any FreeCAD videos for a while but on my list is a video using a combination of OpenSCAD and FreeCAD.