FeatureScript parametric surface

jan_allemann654

Hi there

Working with FeatureScript Parametric Surface:
https://cad.onshape.com/documents/57a62df8e4b03de4c9fcf154/w/f6d71f3d862b522902efcd68/e/ece65382fcd820281a9ee704

I'm trying to model a shape derived from the superellipsoid model:

where a, b, c, p0, p1 is known.

So if i express z = f(x,y), i can create the following shape:


for x,y close to the maximum, the function has an imaginary number as a result. Therefore, I can't create the surface in the corner of the final shape:


from what I've seen in the FeatureScript Parametric Surface i can only set the min, max values for x,y.
I believe expressing y as a function of x would do the job to avoid the corner. Is that possible?

Any other approaches? Final shape should look similar to that:

mahir

I believe a spherical coordinate system would fix your issue. Instead of having portions of the X/Y grid that are imaginary, all values of Theta/Phi would yield a value of R. I think. 

Edit: I stand corrected. It's been a while since I looked at this featurescript. Looks like the spherical option is only for the parametric curve featurescript. So in this case you're SOL. Sorry

mahir

If you don't mind doing some extra legwork, this could be accomplished in construction by generating accurate intermediate cross sections using Parametric Curve. The patches could then be filled in via Fill or Loft.

jan_allemann654

mahir said:

If you don't mind doing some extra legwork, this could be accomplished in construction by generating accurate intermediate cross sections using Parametric Curve. The patches could then be filled in via Fill or Loft.

thanks! yes, i did think about that.
i think i'll give it a try although not super happy with the fill feature in onshape

jan_allemann654

did it with parametric curves. i'd need infinite amount of points per curve to make it theoretically work.
although there is an analytical solution for intersection points, onshape is interpolating the curve between points. therefore, the curves don't really intersect.