Technique Question: NetworkSrf

How do folks deal with ripple in NetworkSrf object.

In this photo you can see a ridge and a smaller depression to the right that I would like to smooth out.

Both of them are at locations I have frames. If I don’t have the frame with the ridge, the whole area budges outwards. With the frame the area to either side the general area is properly depressed, except around the frame itself.

I presume this is a common problem and was wondering hope people approach solving it.

To help, we will need you to post a file with the curves. I suspect the curves in that area will need to be inspected and cleaned up. I’d be looking for extra points, stacked points, or points that cause an overlap in the curve, but that is all guessing without an example.

I’ll extract the data from the file. However, I was hoping that there was some kind of general approach to dealing with this.

In that case, two few frames gives the wrong shape (things go in the wrong direction). Too many gives bumps. I though this would be a common problem where people have come up with ways to deal with it.

It comes down to becoming more familiar with the specifics of the input curves you are using. Using curves with the minimum number of points needed to accurately define the shape, and all curves having the same number of control points are good general rules for improved NURBS surface modeling.

Many times other commands are better suited to making the shape. Don’t get me wrong, NetworkSrf is handy, but I generally use it for something quick where I don’t have time to go to the effort of better input curves. I think it’s better (more easily controlled), than Patch but generally Lofting or Sweep2 gives better results with better input curves.

Problem21.3dm (168.0 KB)

I have played with the one I showed but thinkings have just become bizarre.

Doesn’t look like you understood my reply.
Your curves are a mess. Some have WAY too many points and the curves in the same direction don’t have the same number of points.

Delete the surface, select the curves and press F10 to see the points.

A quick fix is to use the Rebuild command to rebuild the red curves to degree 3 with 4 points and the cyan curves to degree 3 with 14 points.

Select the rebuilt curves and F10 again.
See how they points are evenly distributed and the same number?

Then try NetworkSrf again.
You should get a much better looking result.

Yep, not too good- you might want to set the tolerance at the edge curves in NetworkSrf a little tighter - .0001 maybe, or even less and model at .001 (document tolerances) for things of this scale. But, I agree this is not a good result even so, I’ll poke at it some more. The thing about NetworkSrf is that it should not care about the structure and parameterization of the curves the way Loft or Sweep* etc do. It only looks at the shape of the curves and cooks up its own to actually create the surface. I’m not sure why that fold is generated.

It looks like Network does not like that hook out at the bottom - if you leave the bottom two red section curves out, then you do not get that fold. I’d be inclined to make the surface more rectangular and trim that part out to get the final shape.

Problem21_PG.3dm (216.8 KB)


After rebuilding the curves, I found I got a cleaner surface with Sweep2 using just the two outside cyan curves and the red profile curves.

Thanks for the continuing education.

However, I still get the kink after rebuilding.