I used to do a fair amount of converting scans into usable files. I was given the scan and photos of the object plus the plans of they had them. Mostly different types of containers (juice containers, milk jugs, condiment containers, that kind of thing) I would first bring the scans into Blender and shrink wrap them to build them as a simplified quad meshes and use subdivision surfacing to monitor it. I wouldn't do anything that needed precision like threads or the caps (those were usually garbage from the scan anyways). I would then import those OBJ models into Moi using the SubD and do the fine precise work there. It was relatively fast and worked well. Best of both worlds.
Hi Matadem, From what we gather, scanners still output mesh data first (OBJ/STL etc), then 'reverse engineering'
software tries to rebuild surfaces/NURBS from that afterward. As Michaels post indicates.
QuickSurface looked interesting because it seemed more affordable than the Geomagic ecosystem: QuickSurface
Might also be worth checking out some of the Shining3D stuff as they have both entry level and also
seem to push the “metrology-grade” angle quite hard on some models.
I am not suggesting any of the hardware listed here is good.
Video:
metrology-grade = expensive machines that measure things so accurately they can probably detect your modelling mistakes before you do
I got an old Nextengine laser unit and some geomagic software tied directly to that model a while back and tested it out for a week or two
I only paid a few hundred dollars for the lot but the original full setup bought by universities etc would have been around $30,000, most of it for the geomagic software.
Well I really struggled to make it work and abandoned my efforts after a couple of weeks because I just couldn't make it work for me, and most jobs can be solved with a good set of calipers.
Plus some of the file useage was massive and even my six core computer was taking ages with GM
Anyway. I came back to the STL files with a bit of MOI under my belt and looked at improving scans via MOI and I reckon this is the way to go for us poor people and it's far simpler.
You can use MOI to build the scan into sensible parts, the first part you have to do is the "Origin" part and then you build the other sections around that part to achieve proper squareness in three dimensions
I've done hardly anything on this stuff, it's been a whole new area of learning but the geomagic part for me was abandoned pretty quickly
So my recommendation for a cheapie 3D setup is get a scanner that does good STL files, and use MOI to orientate/Build your result into a full drawing
Which converts to a 75MB MOI stp (about 10 mins)
and a 132MB 3dm file (a few minutes)
It's the processing time for these things when you're just experimenting, it starts to get silly pretty quickly
If you're getting money for a job no doubt it's worth more hassle
edit: I've converted the lumpy 20MB to fbx and it's processing back into MOI
So far I've done the washing up and 5% is done. Going to walk the dog now.
MOI is using 14GB of memory in task manager atm
Did an stl to stp in Alibre 2.5MB to 43MB PRT file (Alibre STP)
saved from Alibre to IGS 137MB
(MOI couldn't open Step Sat files or they took ages)
opened in MOI and saved as a 3DM 287MB
It's a messy subject matter area of work IMO but the ability of MOI to draw inside the scan makes it far more practical
I think my earlier work to get the 20MB file involved mesh reduction in MESHLAB and faffing about with that
MESHLAB is a good program, like MOI it's tightly written and very efficient
edit: I just remembered, if you can get the STL under 1MB then life gets a lot easier.
Hi Ado, I'm not surprised there are problems. The MOI Sub-d importer is not intended to be used on high density scan data with hundreds of thousands of triangles. It's designed to process a sub-d control cage made with a few thousand quad faces.
There's a way to convert STL files to STEP files easily and on the cheap, but the more complex the file, the bigger the STEP file will be, because it'll be made up of loads of triangles.
So my advice is to use apps like MeshLab, which has a few tools for this kind of thing to reduce mesh complexty, and then bring the file into Blender to further reduce the complexity of the STL mesh.
Blender also has some tools for working with meshes and cutting down the polygon count a bit, like the modifier "Decimate" with this you can reduce the size of the STEP.
Here's how to convert STL models to STEP for free:
Import the into FreeCAD and use FreeCAD's internal procedures to convert the model to a CAD part, under the workbench Part and use the command "Shape from Part"
After that, save the model as a STEP file: that's the quickest way.
This way you'll be able to work in Moi3D using snaps and the geometry from the scanned model, but keep in mind that STL models are meant for 3D printing and usually have a ton of triangles, so the exported STEP file will be really heavy to handle.
Of course there are other methods too, but it all comes down to your experience with both the software and modeling itself.
Converting an STL file to STEP format with FreeCAD sometimes took a while.
So my advice is to use mesh modeling apps like Blender and try to make some elements with SubD, then export the model as OBJ, and then convert it in Moi3D using the SubD command.
But there are many methods, and skills you pick up over time.
Last thing; with FreeCAD, you can import STL models and use them as a reference to create the CAD model directly with its built-in tools.
But as I said, it requires experience and it's not the easiest CAD program to use.
Still, it's useful to have it, because sometimes you run into these issues with Moi3D not supporting meshes.
Below in the image you can see an STL file from a laser scan converted using the method I suggested.
Cheers
STL decimated in Blender
STL exported from Blender and converted with FreeCAD into a part CAD
re:
> This way you'll be able to work in Moi3D using snaps and the geometry from the scanned
> model, but keep in mind that STL models are meant for 3D printing and usually have a ton
> of triangles, so the exported STEP file will be really heavy to handle.
There are more problems with this method than just getting really heavy.
It's just fundamentally not the type of data that CAD programs are designed to work with.
No spheres, cylinders, or actual curved objects of any type, just a big pile of trimmed planes.
Hi Michael, I must have misunderstood what the goal of importing an STL file was, since in the first message was mentioned reverse engineering programs, something that actually comes up in professional work, because laser scan data are point clouds that get turned into polygonal 3D files.
In fact, many professional CAD packages let you import mesh files and then reconstruct them using tools that allow you to build on top of the references.
I often work with this kind of data format myself, STL files, and then do the reconstruction file over 3GB and some files I'm working on are over 2GB STL, and I had to reduce them because the full model is over 50GB of RAW data.
So that’s why I suggested this approach, considering that Moi3D doesn’t have a way to import STL files, except for some JavaScript scripts, and I figured that having a STEP file, even if polygonal, could let you do the reconstruction right inside Moi3D's tools.
Hi ado1, could you share that 3D file? That way I can take a better look and maybe I can get you a usable model for your purpose.
Although at this point I have to admit I might not have understood what you’re aiming for by having an STL model imported into SubD, which isn’t possible because of the triangles.
However, if your goal is to have a SubD model in Moi3D, the best thing you can do is re-topologize using mesh modeling applications like Blender, or buy an add-on for Blender, “Quad Remesher”, which costs just over 100 dollars and does an excellent quad-topology reconstruction of 3D meshes, and that lets you import it into Moi3D.
There are issues using those kinds of models directly, though, because Moi3D can’t recognize the sharp edges of subdivision surfaces, so you could still use Blender and other add-ons that let you export the models to IGES or STEP, which take the sharp edges in SubD models into account.
For example this model below was done manually by me yesterday for a beginner user, and I "retopologized" the model with Blender from a file STL of a laser scan.
Hey, I downloaded the STL file and, using Blender with an add-on called “QRemeshify”, I converted it into a quad topology mesh.
Then I exported the model as OBJ and imported it into Moi3D using the SubD command.
I’m attaching the OBJ file below, so you have a model in Moi3D to work on that’s lighter than an STL file.
You can also find QRemeshify on GitHub, but maybe from this link (https://ksami.gumroad.com/l/QRemeshify) you get a version that works with the libraries as well.
However, if you’re dealing with this kind of file, you might want to consider Quad Remesher, which I already mentioned in my previous comment, because it produces a much better remesh.
scan1.jpg
