STEP vs 3MF
ฝัง
- เผยแพร่เมื่อ 16 พ.ย. 2023
- So I noticed something playing with a file I'm making. We all know STEP files are comprised of complete model data and not just a mesh map like in STLs, making them much more dimensionally accurate, but how does that effect a print?
In this case at least, it makes it faster and quieter. Seriously.
I'm pretty sure this boils down to the slicer being better able to implement proper G2/G3 (and other) curve commands. The arcs it will draw come out cleaner because they're printing smoother. As this model was built with printed line dimensions in mind, that also translates to parts printing as intended - and saving a ton of time on travel and repositioning.
I knew STEP was a more accurate format, but I never imagined it could have this kind of impact - a 12% decrease in print time for this model is crazy!
I still defend the use of 3MF format for very busy prints with lots of objects, but for large structural models... I think I'm using STEP now!
UPDATE: I was doing more digging on this and figured out a lot of what'a going on. Studio (and other forks like Prusa and Orca) actually cannot interpret STEP files, so on import they are converted to high-resolution meshes.
wiki.bambulab.com/en/software...
These high-res meshes are generally more accurate than your commonly exported STL/3MF mesh, and result in a higher detection rate for G2/G3 arc commands, as well as more accurate geometry for component geometry.
That's why my boxes are accurately showing the number of walls I expect and printing cleaner, quieter corners! - วิทยาศาสตร์และเทคโนโลยี
Hey I was talking to you over in the Bambu Facebook group. Great video man, straight and to the point. I’m definitely going to give this a try. Thanks for sharing. 👊🏻
This is good info, thanks!
I'm preeeeetty sure that having 'more' sections showing up in the corner, is technically better. I'm not sure where 'its lower quality mesh' is coming into play there, but usually more polygons around a curve, the more detailed it is. But as for printing time, that might be a slicer issue imo. I can't replicate that in Super Slicer at all, they're the exact same time for me between a step file and a 3mf file of the exact same model.
You are correct - more polygons in the mesh results in smoother geometry. That's where I'm pointing out that there are fewer in the 3MF vs the converted STEP.
The default "medium" quality 3MF (or STL) from Fusion will produce larger polygons as compared to the mesh that Studio generates when converting a STEP file. Exporting a "High" quality mesh is roughly equivalent to the result from a converted STEP.
You can adjust the quality of a .3mf when you export from Fusion. It defaults to lower quality. I suspect if you adjusted those settings before exporting you should be able to achieve the same quality obtained by the slicer converting the step to a stl. Not only can you choose between - Low, Medium, High - you can also do a custom. I have found the 'High' refinement settings to produce extremely smooth curves on walls similar to what you found with the .step file imported into the slicer
I looked but was unable to find a quality setting for 3MF. Perhaps it's buried somewhere I missed?
COMPONENTS. That's my issue.
A regular export from the file menu has no quality control, which is what I've been doing. You can't select multiple bodies and perform a "save as mesh" command, but you can combine bodies in to a component and export _that_ as a mesh, where the option to kick refinement up becomes available.
It's nice to have the Volumetric mesh of a 3MF...
I just did this with a random model, compared the slicer gcode of a high 3MF against a step and it looks pretty dang similar - almost identical quantities of G3 commands between the two.
Thanks for making me dig a little deeper!
@@RevHazlett Actually, it doesn't need to be a component. Just 'right click' the body and choose 'Save as mesh' (about half way down) - this popup provides the 'Refinement' choice as well as 'Refinement Options' dropdown for even finer control. It also provides the option to choose between .3mf, .stl (binary or ascii), and .obj
@RevHazlett You have to right click the body and export as mesh. It saves faster too.
And since the lower quality .3mf file took longer to print I bet the higher quality will take even longer!!
I believe the slicer triangulates the step file anyway before generating gcode. I personally manually create a mesh with the desired tolerance, and export that mesh as STL(though I use freecad, not sure of the workflow to do this in fusion).
It does! I learned a bit more about handling exports from Fusion and how the Prusa/Bambu/Orca family of slicers translates STEP files. A "high" accuracy 3MF/STL will generate the same results, just with significantly larger file sizes.
So step is the new king? Is stl and 3mf dead?
When you're looking at geometry, STEP has always been superior to STL in nearly every way. Once slicers started being able to interpret STEP, the only reason to stick with STL is compatibility and, well, habit.
So - yes, but sometimes no.
3MF, at least in it's currently implementation, is still basically just mesh files like an STL. It adds in a bunch of other data (materials, colors, volume, etc) which is an advantage over STL, but I don't _think_ they've started incorporating shape geometry yet. There were a couple of update notes I had read a while back saying it's partially implemented but I at least with what's used in the wild right now I haven't seen anything suggesting true object geometry.
I should have put in this video a side-by-side comparison of the box printed from a 3MF export and one from a STEP export. Once my print queue dies down (a few days) I'll do a short showing a printed side-by-side for comparison. I'm looking at two different lightboxes on the wall right now that are very similar in design and one has noticeable lines along Z in a curve, where the STEP box is smooth.
So to your question, which format is best?
If you've got something where clean primal geometry is critical - like the box I printed with four clean circular edges - STEP all the way. If you've got something with lots of parts and colorization data and you want the convenience of keeping object names from CAD, I'm still doing 3MF.
I'm editing up another silly-long video about the model in this video. You'll see in it I'm using a STEP for the base and a 3MF for the face, for exactly that reason.
@@RevHazlett thanks for that detailed answer! If you extrude parts as components you can also rename them as colors, then it's super easy to see in the slicer what the colors should be when exporting as step. Looking forward to the video 👍👍
@91Renner Yup, I've done lots of "part by color" exports, but I've found myself needing to change print settings for individual pieces a lot (small things with finer lines, individual scaling adjustments, etc).
It's all kinda based on the things I print and how I work with them.
The 3MF consortium is pushing hard that their (justifiably awesome) volumetric approach is good enough. In my perfect world, the couple of them hinting at a spec that incorporates NURBS gets the green light, and we could have the option to basically have STEP-like objects in a 3MF.
More like step vs stl comparison. 3mf is a step file basically which has additional metadata for colors and multiple parts.
Not quite. A STEP files contains the geometry of the shapes within expressed as equations. A 3MF contains a mesh very similar to an STL, but with additional volumetric data to ensure more accurate placement of those polygons. Or course yes, 3MF also keeps object names, color data, etc for it's individual parts.
Think of it this way - a sphere in an STL is nothing more than a collection of triangles positioned to look like a sphere. The higher the "resolution" the smaller the triangles, the finer the appearance of the sphere. With greater accuracy those extra triangles increase file size, in exactly the same way a picture with a higher resolution is larger than one of a smaller resolution. A 3MF is the same mesh, but with coordinate data for points in the mesh as well. Meanwhile a STEP would contain no mesh but instead the formula to render a sphere (I believe by volume, so V = (4/3)πr^3).
The trick now becomes how a slicer interprets those files.
Similarly both STEP and 3MF files can be broken in to their constituent parts, the 3MF winning here as object names and other metadata (color, etc) are retained. However Studio and other variants cannot work with STEP files directly and first interpret the STEP - converting it to a very fine resolution mesh.
That's what we're seeing in the video. The finer quality of the converted mesh from the STEP is higher than the default quality of an exported 3MF so there are more G2/G3 arc commands in the sliced preview. That translates to more efficient printing as there is less repositioning of the nozzle.
A high resolution 3MF will do the same in all honesty.
@@RevHazlett this was a useful breakdown of the finer points of differences between 3MF & STEP files. Thank you! :D
Slicer estimates are never accurate..