In order to create an animated * .gif that would show how to obtain a precise alignment of an "empty" Sketch, I came across this "serious" work plane alignment error through the "Select Plane" function.

Here are four example cases:

a) solid with hexagonal base obtained with "Part Design"

- using two coplanar edges, to define the plane, the work plane does not align, the same behavior if you use an edge and a vertex or three vertices.

- using a face, to define the plane, the plane aligns correctly

b) solid with a square base obtained from primitives "Part"

- using two coplanar edges, to define the plane, the work plane aligns correctly, the same behavior if you use an edge and a vertex or three vertices.

- using a face, to define the plane, the plane aligns correctly

c) solid with a square base obtained from "Draft" (face) + "Part" (extrusion)

- using two coplanar edges, to define the plane, the work plane aligns correctly, the same behavior if you

- using an edge and a vertex or three vertices.

using a face, to define the plane, the plane aligns correctly;

d) prism obtained using the "Additive Primitives" of "Part Design"

- using two coplanar edges, to define the plane, the work plane does not align, the same behavior if you use an edge and a vertex or three vertices.

- using a face, to define the plane, the plane aligns correctly

The animated * .gifs show the four cases mentioned above.

Some of the moderators / developers could kindly investigate (or open a ticket) about this bad and serious behavior of the "Align plane" tool when using solids modeled with "Part Design".

Thank you!

Code: Select all

```
OS: Linux Mint 20.3 (X-Cinnamon/cinnamon)
Word size of FreeCAD: 64-bit
Version: 0.21.29365 (Git) AppImage
Build type: Release
Branch: master
Hash: 59b945dcc329303ad781075ecf30544aab909415
Python 3.10.5, Qt 5.12.9, Coin 4.0.0, Vtk 9.1.0, OCC 7.5.3
Locale: Local
```