But Rhino crashes when I attempt to select the paths for any of the various sweeps which might fill that gap in any way, let alone attempting to put the ridge where I need it. Japhy of tech support suggests posting this on the forum in the hope that someone can suggest a succesful method, so the project is uploaded below. It’s Rhino 7:
Thanks Japhy, but that’s the 2 ridge problem with which I started, having done it on the entirety of the two curves without issue. What I needed to do is replace the problem area identified above with an area with one ridge. I should have been able to do something with sweep 2, but RHino 7 kept crashing. Finally I used networksrf after identifying the boundaries I wanted, and got the intended result, which is shown below. But the reason for this post was the persistent crashing every time I selected a rail to attempt a sweep anywhere in that gap.
When I open your file, I only find the two closed curves that I assume are the rails for the sweep. As you note, using those doesn’t crash Rhino.
If you can provide the exact steps I need to take - or post only the geometry that is involved - I can test to see if that crashes in the Rhino WIP as well.
-wim
If I attempt to sweep any curve or edge along any paths in the area I’ve selected above (either the edges or the coincident curves) Rhino 7 crashes as soon as I click to select the path. Every time.
This is more a courtesy now to the dev team as I’ve long since worked around the problem with NetworkSrf, but it’s such a specific and repeatable bug that I was thinking this report might be of value.
It could be a good idea to draw your initial outline shapes with single span degree 3 or degree 5 NURBS curves and forgo all that joining, which is not necessary in NURBS surface modelling. Then you can simply build lofts with degree 2 across, select the surfaces’ centre CPs, and add the desired crown by moving them all together in the normal direction with the NUV tool. Thus, you obtain very simple curves, surfaces, crown, and you will also have no problem with filleting, if that is needed later.
Thanks Lagom. I used Sweep because other methods I tried gave me a convex result as you have accomplished, but what I need is concave. Maybe that can be easily accomplished in your methods, but I couldn’t figure out how to do it with the lofts I attempted.
Also I edited the lines in this area because offsetting the front curve to create the back curve didn’t give me the relationship profile I required. The curves needed to differe in that one area. That editing resulted in small segments. Short of recreating the entire curve from scratch to match the edits I’m not sure how to avoid this.
It’s good that you’ve introduced the term ‘span’ as it relates to a curve, because I’m not sure what that means, so to fully understand your recommendations I’ll need to find a more advanced tutorial than those I initially learned on. I’ve always put up with kinks when they occur (and adjusted the handles to minimize their obviousness) because I’ve not been clear on why they arise in curves and how to control their presence.
Of course it seems to me that the crashing with what I was attempting (sub-optimal though my methods may be) may still represent a bug, but it’s good to see a path to a better solution.
If you need a concave crown, you just transform the CPs normal, but in the other direction.
For NURBS surface modelling principles, have a look here. It is very important to understand the “anatomy” of NURBS curves and surfaces. Everything starts with single span curves of the right degree, with good curvature. As a bonus, you’ll never see kinks and other nasties again.
I understand, and I very much appreciate your report.
Crash bugs are very much a priority for us, but as with any bug, we need to be able to reproduce it to be able to fix it. Reproducing a bug is often down to extremely specific steps taken in a specific order, so we need as many details as possible.
In this image, I see what appears to be 3 selected curves. When your file is opened, these curves do not exist. Instead, there are these two closed curves:
When I explode these and then join two separate curves from the “top” curves, I get two of the three curves that you have selected in your image. When I use those two as rails and the arc curve in the middle of the “bottom” curve as the shape, I’m able to create a surface without crashing Rhino 7.
As the crash is very repeatable on your end, are you doing something different from what I described? Could you just export the 3 curves that you use and post those in a 3dm file?
Thanks,
-wim
THanks Dale. The crash dump file is huge and contains proprietary information. The file I sent is that Dump file purged for size and stripped of anything proprietary. If you really need it as-is, let me know and I’ll upload it.
Seriously, Djhg, instead of spending ages on troubleshooting something with joined curves, curves pieced together from snippets, curves with kinks, and other problems, I would suggest what I already suggested above - use simple proper unjoined NURBS curves, like you would in any NURBS surface modelling software, and you’ll be laughing all the way to the bank.
