Problem with Curve Modifier (and follow path)


I’m having trouble getting to grips with the Curve Modifier (and have the same problem with Follow Path…) The attached path-problem.blend file illustrates the problem: as soon as “Display modifier in real time” is activated, the object (representing a train track) jumps position. In this case it jumps relative to the length of the path, but in other attempts I have found it jumps in other directions.

The procedure to generate this example was as follows:

  • Add a cube; scale by 0.1 on x and z; Loop Cut And Slide; add a mirror modifier referencing an empty axis, and an array modifier
  • Add a NURBS Path at the location of the empty axis and rotate 90 about z axis; give the NURBS some curve
  • Add a Curve Modifier to the cube: at this point, the cube ‘jumps’.

I have also tried using an alternative method for the Mirror Modifier (moving the scaled cube’s vertices in Edit Mode, to leave the origin at the cursor as reference point) with exactly the same result (path-problem-2.blend).

So, am I missing something in this set-up? How do I prevent the cube object from changing its position when the Curve Modifier is added? I also have an analogous problem when trying to get an object to follow a NURBS Path: having set up the initial positions, adding the Follow Path constraint causes the object to jump away from the path…



path-problem.blend (487 KB)path-problem-2.blend (486 KB)

The second one is the correct one. The origen of the model and the origen of the NURBS curve have to be the same at the begining. for the second blend file you have disabled the preview for the curve modifer by presing the eye.

Sorry for my bad English, but to portray this issue I have to use the translator. I’m trying on a tutorial of Adrew Price and stumble after 8:55 minutes on a problem that I can not explain. In the tutorial: the path is changed and the plane and the cylinder follow the path. In my model, however, it looks like this, as in the attached file. Where is the mistake?


Underground Subway Scene.blend (544 KB)

Apply scale to nurbs path?

Thanks! That was the right thing. But I don’t understand why this isn’t told in the tutorial.

That is one of blender’s Essentials. Check Doubles/Normals is second in this list. :wink: