3D scanned .stl file problem!


#1

Hi

I have an object which i have 3D scanned and imported into rhino. The file is an .stl file. Rhino reads it as a mesh and i have succesfully converted it into a polysurface. Now i want to be able to edit the form but muy problem is that the form consist of 171392 polysurfaces, so its rather large and makes my pc stall. Further more its quite impossible to edit an object consisting og that many small surfaces. Its a cubic shape made up of ca. 30 facets, so i really need to simplify the polysurface form from 171392 surfaces to just 30. Is there anyway i can do that??


#2

Well ReduceMesh does work pretty well, but I doubt it can get a scan from 171K to 30 polygons. If there are really just 30 ‘facets’ to the shape, that’s in the realm of what you can model up manually with the scan to reference.


#3

yeah but the problem is that i’ve made a prototype of a coffee mug im designing, and then 3D scanned it. I have 5 more cups to go, and i really want to use the 3D scan because its the only way i can be a 100% sure i stick to the original. Plus all the angles between the facets is quite difficult to calculate.

Further more, if there isn’t a solution to my problem, I see a rather big flaw with using 3D scanned objects in Rhino.


#4

How about setting up your scanner’s point collection software and your methodology to get a smaller number of points appropriate to the geometry?

Most people I know scan the fewest number of points, not the most, that will get their job done.


#5

Andreas, The current state of the art is not quite there yet where we can make perfect ready-to-manufacture 3d scanned models from real world objects. This means 3d modeling using your scanned prototype for reference is still the only way to get an absolutely clean model.
Can you upload a sample file or image so we can see the complexity you’re dealing with?


#6

i’ve tried the ReduceMesh and it works, sort of. I get a nice result, but the result isn’t a 100% accurate to the original 3D scan.
I know im stubborn but this HAS to work, 'cause how else is the 3D scan going to be a useful method in my designing processes.

I used the new Makerbot Digitizer 3D scanner, its a 1000 dollar scanner, so not the best. It was quite simple, so dont know if i can adjust the scanners point collection etc.


#7

You might want to read up on the following subjects:

Mesh representation of objects
NURBS representation of objects in Rhino (tutorial by Fredrik Wenstøp)
Reverse engineering with Rhino (a bit old but with some good info)
Cleaning up scan tutorial for Rhino (PDF)

–Mitch