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Hey, I'm trying to reverse engineer car part, and I decided to just slice it then surface loft the sketches from ground up. However, I run into the problem where some sketches do not allow me to use them as a building part. I also tried boundary boss/base, which gives me an error for the same items.

The 1st image shows where the issue first occurred to me, but I skipped over it, surface lofting the sketch below and above it together. The next ~8 sketches after produces the same error, however.

The 2nd image shows the same issue as the first image, but in a different area, and I did not loft over it.

The next ~8 sketches after the 2nd image (above the last lofted piece) produces the error as the second and first image's sketches. Like mentioned, the same thing happens with the first image's area, where ~8 sketches above the final loft produces an error.

The 3rd image shows what is trying to be made.

The 4th image shows the same angle as the third image, the lofts/slices, showing where these problems are occurring.

Giving the 5th and 6th image for more perspective of the object, 180 degree view from the third/fourth, and showing the the 3 bits being hollow., respectively.

The problem seems to want to occur where the 'funnels' or 'tubes' are. I tried with less slices, slicing from a different angle, and fixing inefficiency from prior (using two connecting lines instead of one for a closed loft) all did not work individually I also tried lofting more than two connected sketched at once, and this did not work either. I also tried lofting error sketches with no other loft near them, as well as making a new sketch from scratch in which similarly resembles them. Note boundary boss/base did not work either for all of these attempts as well. I did everything exactly the same as the lofts in which did work. Messing with the selection manager didn't work either.

Mind the file being laggy and with some inefficiencies, I'm newish to solidworks, coming from fusion. The inefficiencies seemed to have no effect on the errors though, when trying the same things on a fresh file.

Thanks in advance for any help.

Hello @tdj24, I would suggest you to get a few profiles, both horizontal and vertical to make the main Loft Surface (horizontal as Profiles and vertical as Guide Curves). For the tubes, Loft Surface might work too.

There is also the problem with the sketches. A quick explanation about segments would be this:

Also you cannot convert STL profiles into NURBS and get a good result. STL are made of triangles and all those faces are flat, while NURBS (Non-Uniform Rational B-Splines) are made from splines and create surfaces with curvature.

A quick fix would be using the Fit Spline tool in some sketches to get a more smooth profile for the Lofts. Or you might want to drawn the splines manually for more control.

This project looks pretty advanced for someone new to SW, actually the proper way to do it is with a Reverse Engineer software.

Lucas wrote: ↑Fri Aug 05, 2022 11:44 am Also you cannot convert STL profiles into NURBS and get a good result. STL are made of triangles and all those faces are flat, while NURBS (Non-Uniform Rational B-Splines) are made from splines and create surfaces with curvature.

This is a pretty good explanation Lucas. never knew Nurbs stood for that!

Cheers

Using a SubD tool can help, this is using Rhino3D 7. The why you're doing this is painful and not worth doing. Focus on the known geometries and boundaries to build your features.

Also, the obvious is this mesh gives many clues how the surface modeler created the geometry.

@Tdj24 - So I'm trying out my new headset microphone set up that I got and this is my first new video that I've made using it so please excuse the noobness....

That said I thought I'd dive a little deeper into one of the suggestions about using the Fit Spline aspect of the software for something like what you're doing as I think it will help you to begin to understand what it is that needs to happen. I didn't go into specifically about using the loft/boundary surfacing but at least at the sketch level will show how to get better control.

Also, and this is VERY important, from an optimization point of view your profile should have the same number of segments. (i.e. Square to triangle is not equal as that is 4 sides going to 3. Yes you can adjust the connectors as you go but that can start to get very painful depending on what you need to do.

The number of profiles you have seems like it might be a bit excessive. There is such a thing as "too many" when pairing down the number of profiles in combination with guide curves will help create the shape.

Hope this vid at least helps to give some insight.

https://www.youtube.com/watch?v=Kj0mzojMG18