Equation curve irregular at parameter value 0

[elanzel]

I'm trying to create the involute of a circle using an equation curve.  The equation works fine except when tmin = 0.  I get a error that says the curve is irregular at parameter value 0.000000 (see below).  Has anyone else seen this error and/or found a solution to it?

[awatt]

I've run into the same problem attempting to model a cycloid.  I've also run into it with epi- and hypo- cycloids.

x(t)=1 in * t - 1 in * sin(1 rad* t)

y(t)=-1 in * cos(1 rad * t)

tmin=0, tmax=2 * PI

works with

tmin=0.0004, tmax = 2 ul * PI - 0.0004

But this leaves me with gaps on the ends I have to figure out how to close before I can create a loop to extrude / face.

Second or third derivative analysis is almost certainly where the problem lies.

[johnsonshiue]

Hi! The issue has been fixed in 2017 and later. However, on 2017, the curve can be made with the given equations and range. But, I cannot extrude the curve as a surface. There is still a problem. I will work with project team to understand this behavior better.

Many thanks!