**System Information**

Operating system: Windows-10-10.0.19041-SP0 64 Bits

Graphics card: GeForce RTX 2080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 456.71

**Blender Version**

Broken: version: 2.93.0 Alpha, branch: master, commit date: 2021-03-29 22:00, hash: `rB91c44fe88547`

Worked: (newest version of Blender that worked as expected) 2.92

**Short description of error**

Add mesh XYZ surface producing mesh inconsistent with previous official release. Adds "internal" geometry instead of completing the shape.

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

- Enable "Extra Objects" add-in.
- Shift+A in 3d viewport, Math Function, XYZ surface.
- Enter the formula for a sphere:
- x equation:
`cos(u)*cos(v)` - y equation:
`sin(u)*cos(v)` - z equation:
`sin(v)` - umin:
`-pi/2` - umax:
`pi/2` - ustep: Optional value, used
`72`. - vmin:
`-pi` - vmax:
`pi` - vstep: Optional value, used
`72`.

- x equation:

User notes:

Problem is "fixed" if either of the two actions are performed:

- umax is set to
`pi/2+pi/[u step]`(though this shouldn't matter, mathematically.)

or

- umin:
`0`, umax:`pi`

Both still result in potentially unwanted internal geometry. It is also a notable difference from previous rendition.