Video tutorial: Working with 3D scans

EvanReese

Hey everyone, I've been spending time working with meshes and have a few videos lined up on the topic. The first one is ready today! It walks through my process for scanning an object, then modeling on top of that scan to create a 3D printed part that fits it perfectly. The future videos will cover some new custom features I've been developing for mesh work.

https://youtu.be/rscjUkmr-8g

Caden_Armstrong

I'm really impressed at how smooth that workflow is. Everything from the scan to mixed modelling and then use with a custom feature.
I use to avoid working with meshes at all costs because they were such a pain. Now they seem a lot less scary.

Have you tried larger scans? I'm curious how big of a mesh Onshape can comfortably handle.

MichaelPascoe

@Caden_Armstrong They are still a pain if you try to automate them because we can't really do FS calls in parallel. We can now query the mesh vertices, but even a small mesh may have 10,000 vertices, which quickly overloads FS.

Caden_Armstrong

@MichaelPascoe I didn't mean editing the mesh itself, but just working in mixed modeling mode - like in Evan's video.

MichaelPascoe

Ah, I totally agree. It's really nice to see progress in this direction.

And this is a great video @EvanReese!

Regarding the automation though, here is a simple scan with one of FARO's high end scanners. This is real world data someone would use for CAD. This is not a large model, but for an accurate scan, there are 160,000 vertices.

Almost all of the shapes in this scan are cubes and cylinders. This would be fairly easy to automate within FS if there were a way to handle the data more parallel. Since there is no way to do this in parallel, doing manual clicking and sampling is inevitable, so no automation.

https://cad.onshape.com/documents/e0c6a7cc13c5d087eda9a4e5/w/cc41c1f82a00116701c93e0f/e/401706f2adf992bd74…

EvanReese

@Caden_Armstrong thanks! Mixed modeling has been such an understated game changer honestly. I've not tried bigger meshes yet, but I might just try to scan my back yard and see if it breaks haha

Thanks for sharing that mesh, Michael. Great reference.

MDesign

Nice work Evan. Not sure what the limits are on Mesh imports with onshape but I've always reduced them down. Most of them have way more points than needed. especially areas that are flatter. Depending on the project I'd recommend using a best fit plane FS for fitting a plane to a flat surface rather than 3 point.

glen_dewsbury

Love the video. Thanks.

My first attempt was for not. I believe a different app was used instead of KIRI.

Your video got me going again on mesh conversion. Started with KIRI and not many pictures in low resolution so as to keep processing time down. Needless to say the result was a bit rough.

Any suggestions as to how far to up to push number of pictures at high resolution to get a good enough san for the app to mesh the surfaces together better than I'm seeing. Current scan has bumps under the paper I used for contrast. My sample is a mouse because it was handy. Later trials will go to something much larger like an aircraft engine cowl. May get more detailed later like determining the design an size of the cowl with clearance around the engine with accessories attached. One step at a time.

EvanReese

@MDesign I do have the best fit plane feature in my list, and will use it for sure! I could have certainly stood to do some mesh cleanup before import

@glen_dewsbury I'm far from an expert with it, but good lighting really matters, and objects that have some texture to them work better than smooth shiny ones. More pictures is better. Some of the apps I looked into actually take video as input and you walk around the object 3 times, low, mid and high. I tried a few, but I don't remember if Kiri was one of them.

Derek_Van_Allen_BD

@MichaelPascoe This exact limitation is what keeps me tied to Rhino or Fusion 360 for reverse engineering meshes. I just need the Onshape kernel to expose mesh triangles to us to be able to do face grouping automatically by angle tolerance or size and then I'd have auto replacement of face groups with cylinders, planes, or constrained surfaces.

MichaelPascoe

@Derek_Van_Allen_BD Well you can calculate those as long as you have the vertices, which we do now. The issue is, even with the face normals, we can't calculate anything because FeatureScript currently can't really execute tasks in parallel.

steve_shubin

@EvanReese alway does great stuff.

Along the lines of scanning, here is something I ran across a little while back.

In the forum for a vertical market CAD app used for BIM, Architecture, Landscaping and Theater Lighting and Sound, there was discussion of how to boil down large point clouds to planar walls and such. One person mentioned how his firm used a PointCab product and had good success with it. It works with FARO equipment.

Amongst other things, the website says — Create floor plans and measurements with just a few clicks

https://pointcab-software.com/en/

EvanReese

https://forum.onshape.com/discussion/comment/115923#Comment_115923

Cool! I've not seen that one. There are certainly other dedicated reverse engineering tools out there (Geomagic is another). I'm not sure where the limits are of this workflow, but I was pretty happy with how well it went even doing it the "lazy" way and not having to learn or pay for a new CAD tool only to end up with a .step file at best.