I was trained by CATIA, Pro-Engineer CadKey, Inventor. I don't remember the words "Pad", "Additive Pipe"... etc. I worked in the Automotive, Medical and Rocket industry. I have patents and worked with Patent Attorneys - I don't remember anyone saying "Pad it", we said 'Extrude it". You can call it w...

This should help...

First - syntax: I can't stand the syntax FreeCAD uses - it can be confusing to explain things to other... Who the hell else call an Extrusion a 'Pad' ? Anyway, Familiarity with FreeCAD/Toolbars should inform you that I used the PartDesign wb. The Yellow and Blue stairsteps are the first icons on lef...

As a follow-up note: This week I designed an adapter for a low-cost Metal Feed-Arm I found on Amazon. Updating the Assembly to include the Adapter, Metal-FeederMount and a FeedPort was simple. It's all about Datum's. And, knowing what Origin/Planes to use. That's the part that will take a bit of pla...

For my Sub-Assemblies, I use a 'Part' (the yellow stair-step Icons) For Parts in the Sub-Assemblies, I use individual 'Bodies' (the blue stair-step Icons). These are also individual parts comprised of Features (Pad, Cuts, etc). The Assembly and Sub-Assembly can also contain other items such as impor...

Not sure if this is going to help but, it may lead to further 'inventive' ideas.. is there a way to automatically align the sketch to the edge? Consider the attached: Wherever the part containing the edge is, create Datums for the Sweep Sections and Path. This example is for a Homemade Variable Rad...

Perhaps you already know... It's a cheating approach but, it gets the job done (at least for my needs). You can add Text by using the Draft Workbench's Annotation. It overlays on whatever, including a Sketch. Can set the position and font size, visibility...etc. Example is simply a sketch of a recta...

I'm using v17. No additional add-on's except the Fastener workbench.
The Sketch Mirror is not in default toolbar on v17. Don't know about v18...

I didn't mention:

The sketch mirror tool operates on a Closed sketch, not on a Open sketch. Select the desired sketch to mirror and click the mirror tool.

Of course, you'll want to turn on the sketch visibility = true, or you won't see the closed sketch.

Without your file, I am unable to help resolve the Boolean error.

Try copying the bad boolean file (paste somewhere).

With the bad bool gone, see what happens.

Then, in a new file, open the bad bool and investigate...