I have a series of objects that I have procedurally generated use Bezier or Nurbs curves for which I then attached a Bevel and Taper object.

When I use a Bezier curve the objects come out correctly. See below (ignore the color) enter image description here

However, when I use a Nurbs curve, with the same exact Bevel and Taper object, they come out very distorted. See below: enter image description here

Even when I reduce the size of the bevel object the mesh is still very inconsistent. However, ideally, I shouldn't need to adjust the size at all.

One other point that may be important. When I generated the objects using Bezier curves I would insert a curve and then randomize things like curvature and size to get the final object. Then I would apply the bevel and tapers. However, I created the nurbs curves from a list of 3D coordinates (5994 points) loaded from a CSV(doing something similar to this thread: Poly / Bezier curve from a list of coordinates).

Does anyone know what the cause of the distortion is? Ideally, the objects created from the nurbs curves would look exactly the same as the bezier curve.

Here I've uploaded the files with the Nurbs curves that I'm having trouble with:

And this is the file with Bezier curves that works as it should.

These files are exactly the same except one uses a Nurbs curve and the other uses the Bezier curve.

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    $\begingroup$ Those pictures lack quality to assess the issue, could you post better ones with higher resolution? Also a as simplified as possible file showing the problem would help; hard to tell from the pictures alone. Have you checked the radius property of the curve vertex, those affect object bevel size. $\endgroup$ – Duarte Farrajota Ramos Oct 7 '17 at 1:48
  • $\begingroup$ Sorry about that. I've now uploaded the Blend files in question. The first file is one with the Nurbs curve, the second has a Bezier curve. These two files are essentially identical except for the type of curve I'm using. I did check the radius property just in case but it is the same. Also, as I've noted in my original post, the Nurbs curve is generated from a CSV file. I've left the python code in there just in case. Thank you! $\endgroup$ – switchup621 Oct 7 '17 at 22:50

Your bezier curve based balloon object does not have its scale applied, it scaled 0.25 on all axis, that is why the bevel is not at its true size compared to the bevel object. The NURBS based one is the correct one here.

If you do apply the scale Blender will try to compensate automatically by changing vertex bevel radius to keep the same size so applying scale alone won't fix your issue.

You then have to enter Edit Mode, select all curve vertex and explicitly set the bevel radius back to 1 as described in this answer

A side note, also have in mind that your NURBS curve made from many points is too dense, and will invariably lead to self intersections, rendering and display artifacts caused by the large bevel section relative to point density.

It will also lead to an unnecessarily heavy geometry which is too dense with no discernible advantage. I'd strongly advise severe cleanup or using a cleaner modelling method. See how to clean up curves for some tips


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