Freecad

Freecad is a mechanical design tool. It can be used in

• additive / subtraction mode
• sketching / constraint mode

0.18

Adding Engraved Text to Shape

This is tricky. It seems that it always is (to add engraved text).

Make sure to extrude the text before adjusting x,y,z on the 3d plane. Otherwise the extrusion will be offset by the earlier placement.

See freecad wiki tutorial (0.17). you can skip the sketcher part.

For 0.18, some guides say to use shapestring to trimex. That didn't work for me. Trimex would fail.

However, shapestring, to then PART workbench (not part design)(its bad design they are named similarly is it not? Endlessly confusing.), To then part extrude worked. You must select a font for the text. By default, it won't choose one for you. Not all work.

Ugh. 30 minutes of my life

difference between trimex and part extrude is explained here: https://wiki.freecadweb.org/Manual:Traditional_2D_drafting

Spreadsheets of values

These are useful, but then if you duplicate a part, it makes a new spreadsheet.

External Geometry

When adding external geometry (0.18) you must have a near brandy new sketch. click external geometry, select outside sketch, then draw the rectangle. if you already have a rectangle, it will work. if you already have the rectangle, then add a constraint, then delete that constraint... well it didnt work for me that time. shift - select for Openinventor mouse.

basic example sketch to get used to external geometry tool:

1. start new body, then new sketch
2. make square, horizontal cons. 20mm, vertical 20mm
3. make new sketch (must be a new sketch, make sure it doesn't add this circle to the old sketch)

in new sketch (but still in same body, can't be new body)

1. make circle.
2. give it radius const. 4mm
3. external geometry on top and side lines of rectange. when selected they should turn magenta
4. Now, select two CORNER points, and then click horizontal constraint.

do not select the line (that will give you a blue line/constraint. not what we want) done this way, it should work as expected.

Sketches freezing up.

when adding a constraint, if you get it wrong, you get to a point where you can't delete a constraint just close the sketch (not file just sketch) then reopen and delete.

Symmetry constraint

Note: if you want to define a symmetry constraint with respect to a point, the order of the selection is important, depending on if you select the tool at the beginning or at the end.

   If you click the tool first: select the first point, then the symmetry reference point, and finally the second point.
   If you click the tool last: select the first point, then the second point, and finally the symmetry reference point

Note: above taken verbatim from freecad wiki.

So to get center constraint, do the former, and choose opposite points.

Offset item from center lines

Offset square from center point. instead of symmetrical contraint, or vertical or horizontal, choose the diagnoal line one. then enter an offset, based on a point, and the middle lines. you may have to drag and drop it, to get it on one side or the other.