Surface Modeling Basics and Troubleshooting

 From:  Michael Gibson
4751.12 In reply to 4751.8 
Hi Rogurt,

> Have you considered a debug window?

Yes, I want to have a type of debug console that could give you back error messages. I have not quite yet figured out where to put it in the UI though.

Also for a case like you've got here, there is more than one problem happening - one of the big problems is that one of the surfaces is messed up right near its tip where it has everything collapsing down to a single point, it's folded back over itself right in that area, see this post for a description of that kind of self-intersecting surface:

I'm not sure that a debug window would be able to solve that particular problem.

That one particular surface would be better created by an extrusion that is then trimmed - if you have a solid shape that's like a big block you can do that by directly booleaning the solid block with a 2D profile curve - that will carve the solid into pieces and the caps will be simple extrusion surfaces that are trimmed down, rather than surfaces with bunched together poles at their tips.

The main problem here seems to be trying to build too many things directly to irregular outlines instead of using cutting and trimming methods. Your model will be of much higher quality if it is made up of simple surfaces that have trimmed away portions rather than surfaces with bunched together control points and self-intersecting small areas in them.

Basically something that looks like a 2D profile should actually be generated by a 2D profile and not surfaced directly between 3D curves instead.

Really NURBS modeling is by far the strongest and most useful when you're able to leverage 2D curves more often. If you ignore 2D curves and cutting operations you won't be using the toolset in its best way.

It's easiest to use 2D curves when you focus more on making solid block shapes and then carve the solids up with 2D cutting curves, rather than building your model in a "patch by patch" manner between a completely 3D curve scaffolding.

You can use surfacing to fill in particular local areas, or also to construct a surface to use as a more customized cutting object rather than a 2D curve. But don't try to create surfaces to generally non-rectangular outlines because you'll end up with poor surface quality when they have bad pinching or bunching in them.

- Michael