I use OpenSCAD to create separate files for each color of a multi-color print. Is there a way to import them into Bambu Slicer as parts of the same assembly retaining the color and position as assigned in OpenSCAD? I open the first file as a project then import geometry only of the other files, but they all seem to come in as separate objects centered and anchored to the build plate, not in the position that they were in the OpenSCAD model. I’ve tried importing both .3mf and .stl files with no difference
This is with version 2.7.1.62 on a Mac.
Can OpenSCAD export as .STEP instead?
Hi Mark,
You can import multiple STL files at once into Studio (select multiple files at the same time in the import file dialog). Studio should then ask you if you want to import them all as an assembly or as separate objects. Does that help?
I guess i"m not sure what you mean by separate files for each color, per-se… are they separate bodies in OS? I’m not 100% sure but IIRC one can export a single STL/3MF with all the bodies at once, and then break them back up into parts after import into Studio.
Nah, mesh only unfortunately.
-Max
The process I have been using was to create a separate body for each color and export them using the OS experimental lazy union feature. This created multiple objects in the .3MF file, one for each color. When the .3MF file was imported into BS, it created a separate part for each body, colored properly. I’ve used this successfully for a long time. If I didn’t enable the lazy union feature, there would be one object in the .3MF file but color information was lost.
Since lazy union is experimental, folks on the OS mailing list pointed out that it might change and break my process so I was looking at alternatives. So I was exporting each body to its own .3MF file and trying to find a way to combine them in BS.
But something appears to have changed with Bambu Studio or OpenScad. Now, if I don’t use a lazy union, the file contains only one object when I import it into BS, but the color information is retained.
I hope this makes sense. I’m having trouble explaining it.
Bambu Studio 2.7.1.62 (yes, I know there is a newer version)
OpenScad 2026.02.13
Mark
Studio only supports colors (material) in 3MF files since version 2.5.something (IIRC). So if you updated from a previous version, that’s probably what changed. But watch out, when it applies colors to imported bodies it does so by painting their surfaces, not by assigning a filament directly to that part. Any consequent filament assignment is then ignored (until the painting is erased). So, that’s a mixed bag at best. To avoid the panting step, one must Cancel out of the color mapping dialog during 3MF import (if there is one), or Undo right after import.
So did you try importing multiple files at once?
-Max
PS. very odd, forum says you last posted 11h ago but the feed update just showed up for me a few minutes ago. Sorry, would have answered sooner.
When I tried multiple files at once, with .3MF files it centered each file, which didn’t work aa the colors are not centered to each other. With .STL files it kept the proper orientation. But with either, the color was not preserved.
That change with the Studio version is a possibility for the changed behavior. I was probably using an older version and just kept doing the lazy union thing until I tried without it yesterday.
When you say it only paints the surface, not the whole part, with the way I am importing (without the lazy union) there is only one part. With the lazy union there were multiple parts. I noticed what you mentioned about the painting. With multiple parts all the parts were showing the same filament color, but each was painted the desired color. I could go in and erase the painting and then assign a filament color. I ended up with the same printed result. With the single part (non lazy union), there is no way to further split the part, so if I remove the painting the color is lost and I would have to re-paint as there’s only one filament option.
Mark
Hi Mark,
I guess then I’d just use the lazy union feature if I want to keep parts separate in the slicer but retain color. I haven’t tried it, but I’m not sure why Studio would lose, or not apply, color info when importing multiple STL files at the same time vs. one file with multiple bodies… guess that’s a missing feature or bug because technically the two operations are nearly identical. Same with multiple 3MF files being out of position… seems wrong. But hey, if OS can potentially break a feature in the future, it’s not impossible that Studio will add/fix some! 
EDIT: I don’t know what I was talking about… .STL format doesn’t convey color/material information at all. I was thinking of OBJ format. Sorry, but at least that is solved I’m still not sure about the 3MF parts being mis-aligned after import though.
I also have to wonder about the “might break” OS warnings… single-file multi-body exports seem to be supported by most modern CAD and are quite handy. You may have seen it already, but I did find this Issue over at the GitHub repo, describing what sounds like this exact situation (or rather asking for this feature specifically). There’s the current workaround described there sounds like you’re already using with the lazy union feature (and I guess I must have enabled at some point w/out remembering, because of course I want them separate… I’d union them myself it I didn’t… 
). Apparently there are even utilities that can split a monolithic mesh back into separate bodies… that’s how much it’s a useful/needed feature (though I’m not sure any OS developers responding to that issue actually understand why).
Regarding painting vs. direct filament assignment – if you’re happy with the sliced result then of course whichever is simplest/easiest is likely best. I’ve used that successfully for some flat-wall models which would have been annoying to export as 100 separate parts, for example. But a lot of times painting a model seriously messes with the inside geometry, sometimes introducing walls where none are needed and other wackiness that makes the print much less efficient (or even possibly compromised structurally). It can also introduce occasional “jitter”, as for example shown in this thread or this post. So by “happy with sliced result” I mean the insides as well of course.
Cheers,
-Max
Sorry, just to be clear, are you meaning “visually centered” or numerically centered?
If you’re referring to the defult position, is there some automatic repositioning happening maybe?
I’ve always used the number-based coordinates in the move dialogue to position multiple bodies with precision - as long as the exported bodies all use a common origin that should work for you.
If not, please post your aggregated 3mf if you can, I can try to have a look!
I think I understand what’s going on. When you import a .3MF file into Studio, it centers the X-Y and the lowest Z on the build plate. When I create a multi-color part, it’s unlikely that the different color parts have the same X-Y center and lowest Z, so the parts don’t line up when they are automatically placed on the build plate.