STL vs OBJ - I can use both, which should I use?


I’m preparing to use my community college Fab Lab for my first 3d printing explorations. Since almost all of the discussion on this forum revolves around using .stl file exports for 3d printing, that’s what I assumed I’d use.

But now I find that the slicer software at the Fab Lab can use .stl or .obj files.

Can anybody supply a - hopefully succinct - explanation of the differences/pros/cons of using one vs the other?

Thanks in advance!


simply because they both contain the identical geometric data of the polygon mesh, textures are supported by the OBJ format only but typically not needed for 3D printing.

Regardless what you use, you may want analyze/optimize the data with Netfabb* before processing with the slicer app.

*same as Make version: full blown functionality first, decreases to limited functionality after trial runtime expires.

These are quotes of other posting I have saved:"<<<<
:My first comment is “STL is not a graphics file,” it’s a 3D data format.
My second comment is “STL is intended to be an output file, not an input file <<<<<
What is an STL file? It’s basically a file which “slices” a 3D model into a series of very thin 2D “layers.” This output is then used to drive a stereolithography (or similar) machine which produces physical prototypes through layer-by-layer deposition
This file format is not a CAD format, nor is it a graphics format… it is merely the final step before making that physical part.
Each layer consists of a series of line segments, each of which consists of two end vertices. I >>>>” That means it uses triangles!!
If you have used the stl su plugin before you probably noted it use to show info on the number of trias deleted. I think that has now been deleted with latest release. That was in a recent post plugin in author should have better info.If you use a stl file to repeatedly create a SU model you will find some problems. The bottom line is the stl format does not carry topographical info but approixates with trias:slight_smile:
If you us SU to make a clean model and export to support print that is ok.

Here is a comment on obj .>>> Spline meshes
Converting an .obj mesh file to a smooth T-spline surface is a popular feature in the T-Splines for Rhino plugin because T-spline surfaces are NURBS compatible and can be passed downstream to other applications as a watertight poly-surface. STL files are not recommended for conversion because the model is very high density of triangles and one runs low on memory.>>>>
STL to Su Issues

this is not a quote of me but ‘sjdorst’, stop quoting me wrong and remove frrom your post.