Last time I talked briefly about the limitations that I ran into after tinkering with electronics and using recycled household products as my cases and the inner workings of my builds. I struggled to make anything really impressive because I had no mechanical, electronics or coding training or education. The good news is developing your own intricate case or mechanical design has become extremely fast, easy and the best part is what used to cost thousands of dollars is now FREE!
If you have ever tried your hand at other 3D modeling programs you will remember that first time of immediately feel lost. There are several workbenches in the form of sculpting, texturing, shading, animation, rendering, etc. On top of those workbenches there are endless options and alterations possible with menus within menus. This is how I felt the first time I opened up Blender.
FreeCad and similar CAD software are equally daunting. The good news is it gets easy really quickly and there are a few things I want to share with you in the hopes of making your learning process faster.
THIS IS NOT A FREECAD TUTORIAL. This is merely me showing you the ropes.
5 Things I Learned my First Week in FreeCAD
1. Get Your Mouse Settings Right
This is the first obstacle I ran into. You will notice that you will start FreeCAD and if you create a part with a padded sketch and when you try to move the camera around it isn't very intuitive. It is...weird. Go into your Edit>>Preferences>>Display>>Navigation and change the Mouse and Orbit style to something more familiar. I had played in Blender before so I chose the Blender Mouse option and the Trackball Orbit option with Rotation Mode to Object Center. You do what you want.
2. Workbenches and Add-Ons
The workbenches are the core selling point of FreeCAD. Depending on what you are making or what type of edit you are doing will determine which workbench you will pull up. Think of this as exactly what it is called, a workbench. If you want to sketch out an idea you would use a drawing table and use rulers and all that shit.
The Sketch Workbench is what you want.
If you want to design a new part which will be a car engine you would choose the...Part Design Workbench to add dimensions and pockets of other details because you are designing....a part.
The Path Workbench lets you create CNC like engraves into objects.
The TechDraw workbench is like a 2D blueprint designer kind of like what you might see looking at a patent for an invention.
Etc, etc, etc.
Everything you do is within these workbenches. Just imagine yourself in a big garage, moving from workbench to workbench until your CNC, 3D printed, laser engraved part pops out finished.
The Add-Ons feature is incredible. Go up to the Tools tab >> Addons Manager. This is where you can shop around for other workbenches that will make your life much much easier. Some brilliant people spent a lot of time (allegedly) coding these and allow you to make things quickly such as gears, airplane wings, allow you to attach several parts together or create an exploded view. Add one at a time and play around with it. I suggest you start with a gear or fastener addon.
In the Add-On menu you will notice a Macros tab. Those are python code that automate some work for you but I consider that to be a little more advanced if you are just starting out. So, just know it is there for later.
3. Part, Body, Sketch, Constraints, Pad, Hole
These are the basic building blocks you will be dealing with. Each project you create is called a DOCUMENT kind of like a blueprint. In a fresh new document you need to create a PART which is like a folder that will contain all of your work. Next, you give the part a BODYwhich acts like the compilation of all the dimensions and features you will put in your design. If you have a case with a lid you will be creating a separate body for each. Inside the body you set the basic parameters of your object in your SKETCH.
You can sketch freehand or choose rectangles, circles, etc.
Imagine your 3D part you are designing growing up from the table from the sketch you make. You can make changes to it anytime.
The next is the tricky and most important part of this process if you want any sort of accurate placement, especially if you want to play around with different sizes or make holes or other extensions from the object in the form of other simple shapes.
You should usually add constraints to your sketch. This helps perfect the placement of your sketch and the dimensions of your sketch. For example, if you want to make a box and cut out a hole in it, you would sketch a circle on one of the faces of your box and set the diameter or radius(your choice). Then, you would constrain the center of the circle to maybe the bottom middle point of your box both lengthwise and widthwise. The coolest thing about parametric designing is that you can go back and make changes to your sketch and the constraints. You can change the size and dimensions of your box and the hole will stick to the constraints you choose, holding it in the same place in relation to the point you referenced. In this example, we referenced the bottom middle point on the one side of your box.
Pretty cool huh? This sounds confusing until you try it and surprisingly, it's a lot of fun when you realize how much POWER you hold in your mouse and keyboard. It only takes a few days of practicing this process and you will get it and now you are ready for the next step!
After you have a constrained basic sketch been given the green light on the constraints made on your 2D sketch on the plane you choose (I usually work on the XY plane), you can bring it into the 3D world by PADing it. From there you can adjust the height and sometimes you may want to reverse the direction it emerges into the 3D world. My advice is to play with this whole process until you feel comfortable.
The last thing you need to know how to do is to make a hole. Remember, there are several ways to do this. There is a "Hole" option in the "Part Design' Workbench. You select the Body you are working on to make sure it is active and select the Sketch you want to become the hole. Then you can select "Hole" or "Pocket". I usually use pocket and if that doesn't do it I select the other. You should have magically drilled a perfectly clean hole right where you made your sketch.
Practice this process and play around with some of the options in the Pad and Pocket/Hole features.
Bonus tip: You can move the position of pieces on the body by editing the sketch's Attachment Offset >> Position and edit the X, Y, or Z axis placement. This should move things around for you and may come in handy later.
4. There are Many Ways to do the Same Thing
In FreeCAD there is no "one way" to do something. Although on the surface it can appear and feel superlogical and unforgiving the truth is the exact opposite. The program is VERY forgiving and "open to suggestions". The hole vs pocket decision for example. You can drill a hole in the design both ways. So, if you feel lost or frustrated try and think of a different approach to doing something. Think of additive vs subtractive sculpting. Assuming you are a perfect robot, you could make the same sculpture of the Sphinx using either method and it would turn out exactly the same. If you need to design a toilet bowl, you could build it from a 2D sketch and add other sketches to the body and create curves and grooves. Or you could take a block and cut out the areas you don't need. Or you could make each individual shape and use an Add-On like Assembly to put each part together into one whole shape in a new Document. If FreeCAD had a Tinder or Grinder profile it might read like:
5. Save Often and Click the Refresh to Recompile
Make sure you are saving your work as you make many changes and the software can only walk back a few steps. Also, sometimes you make changes to a sketch or a pad and nothing seems to change. This is when you can hit F5 or Edit>>Refresh to recompile the body and its features. If this doesn't work, restart FreeCad.
I hope this helps you to be less intimidated with the CAD design to STL file process. When you are ready to save it as an STL just go to the document tree with all your changes on the left side and go to File>>Export and save as STL if you want to 3D print it later.
JiF wanted me to let you know that you should click his face and spend the rest of your day watching my 3D printing and electronics content.