Snap to Grid and Snap to angle (15°) were fully engaged throughout these misadventures.
- Draw a 20mm square
- Add a 10mm square in the bottom right corner.
- Trim away the four extraneous lines.
- Draw a 3mm x 0.5mm rectangle to take a second small notch out of the inside corner of the 10x10 notch.
- Trim the two extraneous lines.
- Start a Rounded Corner on the top corner of the small notch and type: 0.5(0000000). Hit enter and get:
- Ø1.000645mm ‽ (No matter what I type, either before hitting enter, or attempting to modify the value afterwards, it always end up the same.)
In an attempt to work out what was going on I Undid back to just after trimming the size of the small notch and measured (everything).
I tried to use the (dumb) Annotate tool to document that there is nothing weird with the lengths or angles; but if there is any way to annotate that two lines are at right angles to each other, I could not find it.
So this will have to suffice:
So then I use the Create Rounded Corner tool to radius that corner and measured again:
Entirely self-consistent. And wrong!
The only thing that stands out to me is that the 0.5mm dimension in the second from last image; and the 1.000645 dimension in the above image are shown in brackets (). Why? Is this documented anywhere?
Maybe you are thinking "It's less than a micron; who cares!". And in the real world of engineering, I agree.
But in CAD -- where it's just numbers -- it frequently means that components drawn separately that ought to mate smoothly, won't! And you end fudging things to get them to do so.
I guess the question for this forum is: Am I doing something wrong in the way I am constructing this?
I've drawn this in a new document to eliminate the perennial problem of unaligned sketch planes.
(Is the only way around that to always sketch in a virgin document and then copy&paste the sketch back to the original document?)