Cura: Cubic Subdivision pattern slightly rotated by default

[evilC]

This is a follow-up from #7541

Application version
4.5.0

Platform
Windows 10 x64
nVidia Geforce 1080 Ti

Printer
Ender 3 Pro

Reproduction steps

1. Place a cube on the bed which is aligned with the X/Y axes
2. Slice using Cubic Subdivision

Screenshot(s)

Actual results
The pattern is very subtly rotated by a degree or two

Expected results
The horizontal lines are properly horizontal

[smartavionics]

Here's something that isn't right, in SubDivCube::precomputeOctree(), the variable infill_angle is given type AngleRadians but initialised with 45 which looks like degrees. Later on, infill_angle is passed to the PointMatrix constructor which looks like it expects a value in degrees. So I would have thought that infill_angle should be of type AngleDegrees rather than AngleRadians. However, with that change, the line orientation is different but still not what I expected. Setting infill_angle to 0, however, has the desired effect.

Using AngleDegrees infill_angle = 0;

Using AngleDegrees infill_angle = 45;

Using AngleRadians infill_angle = 45;

[evilC]

Awesome, thank you @smartavionics

[widget-]

So I would have thought that infill_angle should be of type AngleDegrees rather than AngleRadians. However, with that change, the line orientation is different but still not what I expected.

The 45 degree one? It looks right to me

[smartavionics]

By jove, Sir! I think you could be right, I was looking at the wrong line, methinks.

So, perhaps just changing that one line in the source to declare infill_angle to be of type AngleDegrees will be sufficient to fix the jaunty orientation that it has at the moment. Let's leave that to the UM devs to ponder...

[evilC]

In the absence of adding support for allowing us to pick rotation angle via the UI, could we please have the infill_angle set to 0?
Now that #7541 is implemented and the pattern is centered on the mesh, using 45 degrees will still tend to yield a non-symmetrical infill

[evilC]

Oh, and @smartavionics, any chance of one of your custom builds set like this while I wait for the proper release? Windows x64

[smartavionics]

Sure, I can make a build using:

AngleDegrees infill_angle = 0;

I'll do it tomorrow, I'm too tired to do it now.

[evilC]

Oh and those two commits that went into master too
Much appreciated

[Asterchades]

45 radians ~2,578.31°. If you take out the full loops (7 of) than you're left with ~58.31°. Given the offset angle of the pattern at 60°, that would make for the line going lower-left to upper-right being what has taken that value, indeed putting the entire pattern off by ~1.69°, which matches up with @evilC's rough estimate. So there's almost certainly a superfluous conversion going on there.

Regarding symmetry, rotating by 30° may give the results you're looking for.

[smartavionics]

Hi @evilC , a Windows-64 build that features these changes (including rotation) should be available to download in about 30 mins. Have fun!

[evilC]

@smartavionics Thank you, I can confirm that in your version, everything works exactly as I desire :)

[evtrados]

The PR's from @smartavionics regarding this issue have been merged, so this will be resolved in the next Cura release (i.e., v4.7).