Curvature comb looks like G0 in single curve segment?

I’m just curious as to why the curvature comb reports a result like this on a single curve segment:

The curve was generated by intersecting two single span surfaces, and it cannot be exploded.

How is it possible that it “appears” as if there’s only positional continuity within a single spline, even though it’s multi-span? I didn’t think curves could be G0 internally?

just guessing but the curve is not single span if it have degree 3 and 8 cps. also the rebuild tool shows the control points, not the the kinks where the discontinuity may happen.

Right, but not down to G0?

Here’s the same curve analyzed in Alias (exported via IGES):

Here, it is at least G1, which is what I expected.

So, my question is, it is just a quirk of the curvature diagnosis drawing in Rhino?

Hello - I’ll ask… but I believe the combs in Rhino follow the torsion - osculating plane - of the curve; there may be a discontinuity in that. If you run Curvature and put on the Knot Osnap - it will, I am betting, snap to that location and you will see (I am betting) that curvature circle snap from one plane to another as you pass that spot.

-Pascal