Hello again, this time I share a method to loft a surface.
I am going to make a loft surface with all these curves of different styles (i.e, different point counts, or polycurves). I can do it with rebuild option of loft, but i always use a slow method for better shape.
I start with the longest curve, the red one, rebuild it to as less point count as I can. I choosed 18 points degree 3.
use sweep 2 rail, use upper and bottom short straight lines as rail, use red curve as section to make a surface.
the created surface will have 3 curves fits with the surface, only one dosn’t fit. I use matchsurf so that edge “fits” on the curve.
delete the curve that just for matching, and duplicate the curve from the edge that just matched.
repeat all above step to replace all curve to same style
perform loft after all curve are in same style
I think this is very slow but it is a better control to the final outcome. It will be a tidy one piece of surface.
This model is started with scanned mesh, and then I used Quadremesh, to subd, to nurbs. However I am not satisfy with the result, I use many planes to extract intersections so thats why, so many curves, so many pointcounts that looks like network surface.
Did you start from a mesh to get so many points? With a mesh more points can produce a more accurate representation of a surface. One of the advantages of NURBS is that they they can produce a surface to any level of accuracy with a much smaller number of control points. You certainly have the right idea in reducing the number of curve control points, but why choose 18?
It seems to me that you could reduce to even fewer, perhaps 3 or 4. Then, as Gijs points out, you can certainly, using the same reasoning, reduce the number of curves controlling the other direction - possibly just one at each end for some surfaces, but perhaps 3 or 4 in your case.
Finally, you may discover through experimentation that sweep 2 rail will give a better result than loft.
Yes it is too many curves, I can use 1/4 of them, the surface will be more clean but it starts losing the shape, and I am still figuring out how to use less curve/ use less point count to get clean surface as well as precision.
Well basically, don’t use Loft, it’s a dumb tool that dates back to the dawn of 3D and has no relationship to proper NURBS modeling technique, exists only because “hey I guess if we have some curves we can make a surface pass through them, that’s cool right?”
Yes it is from a scanned mesh, but the scan quality is poor at the edges so that mesh piece is only useful to locate the position of surface and approximate shapes, yes 3 or 4 point is possible for this cross sections. I will try that out.
sweep2 also make simple and clean surface when I place sections on curve edit point, it can adjust continunity and I use it as well.
the rebuild option inside loft command is quick way, but the control point location is automaticaly calculated by loft command and not kind of “manually” placed
RebuildNonUniform is alot better than my slow way!
I care to disagree, especially when making loose lofts. They behave very predictably, and allow you to control end tangency in very much the same way as defining a Controlpoint Curve. Placing sections on controlpoints of a curve, makes that the loose loft matches exactly with that curve:
@Gijs here I don’t get the logic of using “sections curves in between”. They are actually not the “sections” of our expected surface but kind of an “offset curves”.
I only know with “loose” option a smoother surface can be created but they are not following the section shapes in between in between two ends, so the result of this way is “less predictabe” “for me”.
Your method may have all 4 edges following the input curves but not really following the input curves inside 4 surface edges.
think of it as a way to control the edge conditions of the surface, but also have control over the internal points of the surface. Loose loft gives you a surface that matches exactly with the control points of the input curves.
I guess it is a matter of preference. There are multiple ways to create clean surfaces. For primary surfaces EdgeSrf and LooseLoft are my favorites. In some cases you can create identical results with Sweep1 and Sweep2, if certain conditions are met.
the much more powerful feature would be to make simple-Sweep more accessible and give more feedback why it fails.
I think it was a big mistake to hide this feature instead of making it more accessible (better feedback - more tools (for example constraints, fix point to editPoint))…
simpleSweep allows exactly what is much more intuitive:
draw curves that lay on the surface.
@VinPo this relates to the workflow I wrote you in a private message
