Hard edged points on curves

another bug i get almost everytime i make curves are these random hard points/kink in the curve.

so i can draw a curve, but if i connect others together and blend or merge after a while i end up with 1 or 2 points that are broke. they create hard angles and do not blend.

i can delete them, however the kink in the curve just moves to the next point and so on.

if i hold down on the kinked points i can only delete, i cant disconnect it and try to blend the two edges.

workaround is delete the entire curve and try again. deleting point all the way down to 2 still leaves the kink in the curve. when it occurs it cant be removed. i cant attach an image if it isnt clear.

Here are some images to make it bit clearer

Here is also another issue I get a lot. A curve that is seemingly perfectly symmetrical will often not be truly that way.

The image below you can see a curve with equal points on both sides but yet the left is different.

Generally this bug and ones above I get almost every time I merge/blend/combine curves. Like some info from each previous curve remains

@Yaniv, do you know what causes:

  1. The kinks in the first photo (the line somehow breaks after adding/deleting control points)
  2. The asymmetrical control points in the car’s front curve, although the lines were created in symmetry mode.

@Mark1 would you be able to send us the model as UMK to hello@umake.com or upload it here if you feel comfortable with it.


@evi @Mark1,

When a complicated curve is drawn, a one tha cannot be described as a single NURBS with no more than a few control points and still be very close to the curve the user drew, we construct multiple NURBS and connect them to to a single curve in the uMake world. The connection is marked with a blue dot filled with blue when using the edit points tool. When these control points are edit a sharp shape will be created. I can’t tell from the images attached if that is the case for Mark, but it make sense that it is.

As for the curve not being symmetrical, is the curve was originally drew as an arc and then edited to the shape in the image? Because that could explain it. An arc is a special NURBS in the sense that its control points does not have equal weights, so starting from an arc or a circle and edit it or deleting some of its control points can have this a-symmetrical effect.

I am offering reasons for these 2 things. It can also be something else, like a bug. If the reasons I offer does not make sense , a file with these problems will definitely help identifying the reasons.