CAD Forum

I am helping with a B-17 restoration project and we recently had a major component scanned.  It is a big part and the STL file is large at 440MB.  The scan has some holes in it.  We can see the STL using the slicer software for a 3D printer, but this file just bogs down SWX.  I am using SWX Pro 2020 and also have 2021. 
Does anyone know if SWX 2022 has more capabilities to deal with STL files?  I have not bothered to install 2022 yet, but will if it can give me something usable. 

Is there a SWX add-in that can do the job? I have no experience doing surfacing so this seems intimidating.

Since we can open the file in Chitubox slicer software rather easily (it even slices it despite the holes in the scan) is there a slicer program that can convert (Save As or Export) to a usable file format?

I was able to open a smaller scan with similar holes in Onshape and saved it out as STEP, Parasolid, ACIS, Object, and IGES formats, but if they opened in SWX they were still the unusable mesh surfaces.

If we can get this STL converted to surfaces or something we can reference then we can repair the holes and make a complete solid. 

Our objective is to eventually get a casting of this part.  We do not have drawings for it, apparently they don't exist (according to the professional historian leading this project - - and he's found just about everything else!)
Thanks in advance.

From what i heard, SW22 add some new capability to editing STL file, but performance wise is still pretty much the same i think?

My personal practice when rebuilding large (non-organic) STL file in CAD:
1. Simplify the model // Reduce the resolution using MeshMixer if possible
2. If thle STL is still relatively large and heavy, split the part in MeshMixer, work on a smaller and more manageable portion and combine them afterward

If you can make the STL file available as a download somewhere, I can open it in DesignX and have a go at repairing the holes and turning it into SW geometry.

DennisD wrote: ↑Sat Apr 02, 2022 3:50 pm Is there a SWX add-in that can do the job? I have no experience doing surfacing so this seems intimidating.

I was able to open a smaller scan with similar holes in Onshape and saved it out as STEP, Parasolid, ACIS, Object, and IGES formats, but if they opened in SWX they were still the unusable mesh surfaces.

If we can get this STL converted to surfaces or something we can reference then we can repair the holes and make a complete solid. 

We have some discussion about it here: viewtopic.php?t=1264

I don't know Onshape tools, but sounds like you saved the Mesh Data inside a Step, you need to convert the mesh to NURBS so you can use it as surfaces.
For that you will need a Reverse Engineer software, like Geomatic DesignX, PolyWorks Modeler etc. Rhino7 has QuadRemesh as an affordable option.

You could also fix and decimate the mesh in a specialized STL mesh editor or a 3D computer graphics software (Blender, ZBrush, 3DS Max, Maya), lowering the amount of data makes it better to import in SolidWorks.
Those software can't convert it to NURBS, the STL mesh will be more like a reference 3D image while creating sketches/features in SolidWorks.

JSculley wrote: ↑Sun Apr 03, 2022 10:38 am If you can make the STL file available as a download somewhere, I can open it in DesignX and have a go at repairing the holes and turning it into SW geometry.

I look forward to any help!! I sent you a PM so you can get the file.

hmm,..just place the STL data on a public server bcuz everyone likes old historic planes and wants to help?

zxys001 wrote: ↑Tue Apr 05, 2022 10:54 am hmm,..just place the STL data on a public server bcuz everyone likes old historic planes and wants to help?

The file is here. https://drive.google.com/drive/folders/ ... sp=sharing
If it can just be converted into something I can use in SWX I can then fix the problems caused by the scan.

I appreciate any help!!

..it's definitely a challenge.

zxys001 wrote: ↑Tue Apr 05, 2022 11:15 pm ..it's definitely a challenge.

Wow, Paul! This looks terrific already! I'm interested in the steps and tools you used to get there. And of course I'm hoping you'll share the file.

Dennis - quick question - what version of SW are you guys running?

I'd like to also give it a shot if I have time in the evenings.

Austin Schukar wrote: ↑Wed Apr 06, 2022 12:02 pm Dennis - quick question - what version of SW are you guys running?

I'd like to also give it a shot if I have time in the evenings.

Austin, I have SWX Professional, 2020 and 2021 installed on my computer, mostly using 2020 for this work. I have not yet seen a burning need for it, but I am current on my license so I can install 2022 if necessary.

Actually, I'd be happy with a dumb solid.

I am guessing what you really want is good solid model of the part. Ed Eaton gave a good presentation on using scan data to build a model at SWW a couple of years ago. https://dimontegroup.com/solidworks-wor ... rvy-stuff/

I tried just doing the base-revolve that seems like the main feature, I think it came out pretty good for something really quick and dirty. I think this is the route you will want to take if you want to recreate the part with something other than a 3d printer.

Was this originally a sand cast aluminum part, or how was it made?

bnemec wrote: ↑Thu Apr 07, 2022 9:35 am Was this originally a sand cast aluminum part, or how was it made?

I do not know all the specifics of the origins of the part and I have not seen it in person. The folks working on this aircraft rebuilding project are all over the country. If we had the drawings all would be made clear.

This part was made in the early 1940's for a B-17. I suspect the only viable option for making it at the time was by sand casting. The part that was scanned is from a surviving aircraft so it had been finished. Probably not all the surfaces were machined or hand-worked, but certainly some were.

Our goal is to develop a solid file that represents the part we scanned and then to use it as a starting point to talk with sand cast vendors. With their feedback we will add material to the model to make a configuration for the cast version. Any shrink factors they need would be easy enough to apply as well. From there they can use the cast configuration to make the patterns for the sand casting.

Easy peasy.

Hey Dennis, can you verify the STL units or just rough dimensions of the tub?

Had some time today to study this.

I reduced the triangles in Magics so it is easier to import in SW and use it as a reference image to create the solid:
One has 16MB and other 3MB

Btw, this scan should not be done in fine mesh quality. It will create huge files like the original one and will be super hard to work with it.
Also using a scan spray to increase the quality and reduce noises is a good idea. A few minutes improving the scanning can save up hours fixing the mesh later.

I tried the semi-auto fix method in Blender as explained in the other topic I mentioned.

Basically I had to split the part in four to use the Remesh Modifier so it wouldn't crash; later I did some boolean to stick them together. I also send it to Magics and did a ShrinkWrap to get a better mesh. The final result got less details, but its watertight and 3D Printable. 12MB
I also added some geometry to it in Blender (two cylinders and fixed one hole), but I am not a Hardsurfacing artist. Guess it's a good idea to study it lol

After that also tried to get a NURBS solid in Rhino from this file and from others (have like 8.5GB of this stuff here lol). Unfortunately I failed, maybe @zxys001 could help with that.
Got like 40,000 surfaces. I need to check how to lower it before use ToNURBS. It's pretty difficult to get a good quality SubD from the mesh, probably due to the propagation of deviation and also the lack of symmetry. Will try again next week.

Hello Dennis....when converting data from a 3D scan geometry it is always, 100% of the time, best to capture as much as possible in the beginning as there is a direct exponential 1:1 in terms of bad scan data to file fixing that needs to be done in post processing. What I would say is that whom ever did the original scan missed A LOT that, even if converted to a BREP model it will need a ton more file fixing.

Do you know if there is any additional access to the physical model?

Arthur NY wrote: ↑Thu Apr 14, 2022 12:49 am What I would say is that whom ever did the original scan missed A LOT that, even if converted to a BREP model it will need a ton more file fixing.

This data has also been fiddled with a bit. It looks like someone started to try to clean it up, but obliterated some detail. Here's one of the more obvious spots:
Notice the circled boss on the left, and how the corresponding boss on the right has been 'covered over', probably in attempt to fill missing data on the side of the rib that was in the shadow from the scanner.

I all reality it really should be taken back to the beginning and scanned again thoroughly. There's just too much missing data to try and reverse engineer this properly.

Arthur NY wrote: ↑Thu Apr 14, 2022 12:50 pm I all reality it really should be taken back to the beginning and scanned again thoroughly. There's just too much missing data to try and reverse engineer this properly.

@DennisD I think you said somewhere you were just given this scan and do not have the physical part. Do you know if the part is removed from the airframe and if so where in the country it's located? If it were near me, I would want to get it into our tool room CMM where the tech could scan it as well as gather point data for obvious primitive geometries. We've found that using probed points to recreate basic model features instead of trying to blend triangles then combine those bodies with something from the scanned data works pretty well.

I am happy to report that we have a solid file!

Let me clarify a few things. The part was scanned by someone else. I only got involved after the fact. The scanner apparently just wanted his money for scanning and did not care too much about the results because there were a lot of problems with the file. But, no, we could not go back and get it rescanned. We had to deal with what we got. The customer is a non-profit working to rebuild a historically accurate WWII B-17. https://www.facebook.com/hangarthirteenfoundation

Though this particular part is very large the situation is even larger. MANY people have this problem, i.e., scans that have holes/problems and STL files that are difficult to work with. I knew there would be many of you that would see this post and offer help. We were just looking for a solution and we did not have the skills or software to get it done. We now have a solution and I am happy to share the information for the benefit of everyone that encounters this problem with scanned files.

nPower Software (https://www.npowersoftware.com/) makes an add-in for SolidWorks called Power Surfacing RE for reverse engineering. They were a joy to work with! Gary Crocker was on the phone with me for almost two hours as we shared screens and figured some things out. He is the president and the main programmer. They have taken a different approach to this type of problem and have developed some tools and capabilities that nobody else has achieved. He was telling me about some of the things they were able to do for the movie industry CGI. Most impressive!

He even took it upon himself to have his team use this problem in a 50-minute tutorial video. Check it out:

I just wanted to share that there is a solution out there that works with SWX. It still takes time and skill, but so does everything we encounter.

I want to thank everyone that contributed to this thread. All of the comments helped provide insights and ultimately led to a solution. In particular, thank you, nPower for your help!

Hey @Alin,
I see you've got a thread going about importing stl files. But, I didn't see you comment on this thread. Looks like Dennis found a solution. But, I figured I'd bring it to your attention.

mattpeneguy wrote: ↑Sat Jun 18, 2022 10:03 am Hey @Alin,
I see you've got a thread going about importing stl files. But, I didn't see you comment on this thread. Looks like Dennis found a solution. But, I figured I'd bring it to your attention.

Spectacular! Thanks for pointing this to me, Matt!

That's simply amazing!