I'm trying to rescale a loop of rope without changing its diameter. That is, I want to increase the distance between the rings (some shown selected in this screenshot) ... but keep the rings themselves the same size.

enter image description here

Oh, and this is for a DAZ Studio morph, so I need to adjust the mesh without adding, deleting, or renaming any geometry. Is there a quick and easy way to do that, or will I need to select and move each ring in the loop?

Thanks for your help!

-- Problem Solved but not Question NOT Answered --

Clarification: I modeled this rope in Blender, using a cross section object and the Screw and Curve modifiers. I then applied those mods to get the mesh shown above and assigned Vertex Groups, which became bones when I rigged the figure in DAZ.

My rigging scheme for the loop uses seven bilateral bones: Base, Top, Top-Sides, Sides-Top, Sides, Sides-Bottom, Bottom-Sides, and Bottom. Imagine a pocket watch where the winding stem is the Base, the arc from 11:00-1:00 is the Top, the arcs from 10:00-11:00 and 1:00-2:00 are the Top-Sides, etc., down the loop to the arc from 5:00 to 7:00 at the Bottom.

enter image description here

I used bilateral bones -- rather than bones that start at one end and follow the loop down and back up to the other end -- so users won't have to precisely counter-rotate bones to realign the ends. It's easy to pose the loop, using each bone's Bend and Twist controls. But I thought I would need morphs to make the loop larger or smaller.

Problem Solved: As it turns out, I can make the loop larger or smaller, simply by using the bones' Scale sliders. That changes the diameter of the rope, but I can set limits on the Scale slider so the change in rope diameter isn't noticeable. So I don't need morphs to change the size of the loop.

Question NOT Answered: But that doesn't answer my question of how to expand the distance between parts of a mesh without changing the parts' size -- in this case, the rings that form the rope -- and without adding or deleting any geometry.

That italicized part is crucial, because a DAZ morph works by comparing the position changes of each vertex in the original and morphed meshes. It's not enough that the morphed mesh has the same number vertices, connected in the same ways. The vertices must also be in the same sequence in the underlying file.

For example, you can't use the Mesh>Symmetrize function while making a morph, as that deletes half of the model and replaces it with a mirror image of the other half. That changes the sequence of vertices in the underlying file, so DAZ's Morph Loader won't recognize the new mesh as a morph of the original.

@MrZak suggested a Curve modifier to deform the mesh. But I think that works like the Symmetrize function: applying the modifier deletes the original mesh and replaces it with the deformed mesh.

So ... does anyone know if applying a Curve modifier deletes-and-replaces the mesh?

If it does, I can't use it to make morphs, because the order of vertices in the obj file won't match the original.

But if it doesn't, it would be ideal for problems like this. I have the original curves that I used to create the model. I could copy the original curve, use it in a Curve or Deform mod on the mesh, adjust the control points, apply the mod ... and export the morphed mesh.

  • $\begingroup$ You could try to create a curve (e.g. select edgeloop from the rope, duplicate, separate and convert to curve), add Curve modifier to the rope and adjust the curve to get the desired shape. Tweaking Curve modifier can be tedious though. $\endgroup$ – Mr Zak Apr 3 '17 at 12:37
  • $\begingroup$ Hi @MrZak ... Once again, this is for a DAZ morph, for which the workflow is: (1) import the mesh obj, (2) move vertices, edges, and/or faces, and (3) export the mesh obj. I can't add, duplicate, delete, or rename any vertices, edges, or faces ... or DAZ will not recognize the imported mesh as a morph of the previously exported mesh. $\endgroup$ – Crissie Brown Apr 3 '17 at 13:04
  • $\begingroup$ I didn't suggest directly editing mesh data for the rope.. The only mention of duplicating was for creating curve which was supposed to be used as a target for modifier; the rope itself should not be touched. Curve modifer is of Deform modifiers which doesn't create any new geometry. $\endgroup$ – Mr Zak Apr 3 '17 at 14:32
  • $\begingroup$ Thanks @MrZak. Please see my clarification at the bottom of the original question. $\endgroup$ – Crissie Brown Apr 3 '17 at 19:02

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