**System Information**

Operating system: Windows-10-10.0.18362 64 Bits

Graphics card: GeForce RTX 2080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 436.48

**Blender Version**

Broken: version: 2.81 (sub 13), branch: master, commit date: 2019-10-04 22:33, hash: `rBab519b91b2c4`

Worked: (optional)

**Short description of error**

The inset faces tool doesn't have the vertices track exactly along an edge. In many cases it's off enough to cause modelling problems.

**Exact steps for others to reproduce the error**

- Default startup file. Delete the cube.
- Add a cone, radius 5, depth 10.
- Go into edit mode and select all of the faces of the cone except the circle.
- The edge length of the long edge is sqrt(5^2+10^2)=11.1803398875. Inset the edges by that amount.
- Zoom in and have a look at the tip of the cone. The vertices are off significantly, not just a little bit. The vertices actually converge at around z=5.097 instead of 5, which is 1% off over a distance of 10m. Thus the inset faces tool is not tracking correctly along the edges. I think 0.5% to 1% error, depending on how you calculate it, is unacceptable for such a simple mathematical operation.

- This happens at any scale. Make the cone 50m radius and 100m tall and you get the same issue.